Nanofiber sheet, method for using same, and method for producing same

ABSTRACT

A nanofiber sheet includes: a substrate layer; and a nanofiber layer located on one surface side of the substrate layer and containing nanofibers of a polymer compound. A peripheral edge of the nanofiber layer has a thickness of from 0.1 to 10 μm. The nanofiber layer includes a gradation region having a thickness that gradually increases inward from the peripheral edge. The distance W1 between the peripheral edge of the nanofiber layer and a maximum thickness portion where the thickness becomes the greatest in the gradation region is at least 3 mm. A nanofiber sheet manufacturing method involves depositing nanofibers onto a collecting unit by moving at least either a nozzle or the collecting unit, to thereby manufacture a predetermined nanofiber sheet including a gradation region.

TECHNICAL FIELD

The present invention relates to nanofiber sheets, methods for using thesame, and methods for manufacturing the same.

BACKGROUND ART

Fiber sheets made by depositing nanosize-diameter fibers (also referredto as “fibers” hereinafter) by electrospinning are known for use ascosmetic sheets that are attached to the skin to conceal spots andwrinkles. For example, Patent Literature 1 discloses a cosmetic sheetincluding a hydrophilized substrate sheet, a nanofiber sheet, and acover sheet. Patent Literature 2 discloses a cosmetic sheet made from ananofiber nonwoven fabric impregnated with a cosmetic serum containing acomponent serving as an adhesive.

As a method for manufacturing the aforementioned nanofiber sheet, PatentLiterature 3 discloses a nanofiber sheet manufacturing method whereinnanofibers are deposited by ejecting a polymer solution from an ejectionopening applied with a high voltage, while moving a jetting device in azigzag manner. Patent Literature 4 discloses a manufacturing methodwherein a nanofiber nozzle is located at a position that allowsnanofibers, which have fallen outside the end portions of a collectionsheet, to be electrically adsorbed onto a portion on the back-surfaceside of the collection sheet. Patent Literature 4 describes that thedisclosed manufacturing method can yield a sheet in which nanofibers aredeposited so as to go around to the back-surface side of the collectionsheet. Patent Literature 5 discloses a manufacturing method including anend-surface processing means that removes the width wise end portions ofa nanofiber nonwoven fabric obtained by electrospinning. According toPatent Literature 5, it is possible to manufacture a nanofiber sheethaving a constant thickness up to its end portions.

Patent Literature 6 discloses a method for manufacturing a polyurethanenanofiber nonwoven fabric, involving: ejecting a polyurethane resinsolution while moving the tip end of a nozzle in a circular motion; anddepositing the polyurethane resin solution on a collector that moveslinearly while rotating. Patent Literature 7 discloses a nanofiber filmmanufacturing method, wherein an ejection means ejects a material liquidwhile reciprocating back and forth within a plane parallel to acollection surface which is arranged in opposition to the ejectionmeans.

CITATION LIST Patent Literature

Patent Literature 1: International Publication WO2014/125407

Patent Literature 2: JP 2013-28552A

Patent Literature 3: JP 2008-196061A

Patent Literature 4: JP 2011-84842A

Patent Literature 5: JP 2013-227688A

Patent Literature 6: JP 2009-108422A

Patent Literature 7: JP 2011-084841A

SUMMARY OF INVENTION

The present invention relates to a nanofiber sheet including: asubstrate layer; and a nanofiber layer located on one surface side ofthe substrate layer and containing nanofibers of a polymer compound.

Preferably, a peripheral edge of the nanofiber layer has a thickness offrom 0.1 to 10 μm.

Preferably, the nanofiber layer includes at least 3 mm of a gradationregion having a thickness that gradually increases inward from theperipheral edge.

The present invention relates to a method for using the aforementionednanofiber sheet.

In the aforementioned method for use, it is preferable to place thenanofiber layer in contact with a surface of an object, and use thenanofiber layer in a moistened state.

The present invention relates to a laminate sheet including: a substratelayer, and an ultrathin sheet located on one surface of the substratelayer.

Preferably, the ultrathin sheet has a thickness of from 5.1 to 500 μm.

Preferably, the ultrathin sheet has a contour shape corresponding to anapplication-target section to which the ultrathin sheet is to beapplied.

Preferably, the ultrathin sheet includes a tapered peripheral edgeregion having a thickness that gradually increases inward from aperipheral edge of the ultrathin sheet.

Preferably, the substrate layer includes a region that extends outwardfrom the peripheral edge of the ultrathin sheet.

The present invention relates to a method for manufacturing a nanofibersheet, involving ejecting a material liquid from a nozzle while applyinga high voltage between the nozzle and a counter electrode, anddepositing, onto a collecting unit, nanofibers produced from thematerial liquid by electrospinning.

Preferably, in the manufacturing method, the nanofibers are depositedonto the collecting unit by moving at least either the nozzle or thecollecting unit.

In the manufacturing method, it is preferable to manufacture apredetermined nanofiber sheet including a gradation region having athickness that gradually increases inward from a peripheral edge.

The present invention relates to a device for manufacturing a nanofibersheet, including: a nozzle configured to eject a material liquid(spinning liquid); a counter electrode located in opposition to thenozzle and configured to create an electric field between the nozzle andthe counter electrode; a collecting unit configured to collectnanofibers produced by electrically stretching the material liquid; anda mechanism configured to move at least either the nozzle or thecollecting unit.

Preferably, the manufacturing device is configured to be capable ofdepositing the nanofibers onto the collecting unit while moving at leasteither the nozzle or the collecting unit based on data of a movementpath inputted to a control unit.

Preferably, in the manufacturing device, data on the movement pathdetermined in a path calculation step is inputted or is inputtable tothe control unit.

The present invention relates to an ultrathin sheet manufacturing methodfor manufacturing an ultrathin sheet by ejecting a material liquid froma nozzle and depositing, onto a collecting unit, fibers or particlesproduced from the material liquid.

Preferably, the ultrathin sheet has a thickness from 5.1 to 500 μm.

Preferably, the ultrathin sheet manufacturing method involves anintended-shape forming step of ejecting, based on information relatingto an intended contour shape of the ultrathin sheet, the material liquidwithin a range of the contour shape of the ultrathin sheet while movingat least either the nozzle or the collecting unit.

Preferably, in the intended-shape forming step, the material liquid isejected so as to form a tapered peripheral edge region having a width of5 mm or less and having a thickness that gradually increases inward froma peripheral edge of the contour shape.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view schematically illustrating an embodiment of ananofiber sheet of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

FIG. 3 is a perspective view of the nanofiber sheet illustrated in FIG.1.

FIG. 4 is a schematic diagram for illustrating an inclination angle of agradation region illustrated in FIG. 2.

FIG. 5 is a diagram, corresponding to FIG. 2, schematically illustratinganother embodiment of a nanofiber sheet of the present invention.

FIG. 6 is a diagram, corresponding to FIG. 2, schematically illustratingyet another embodiment of a nanofiber sheet of the present invention.

FIG. 7 is a diagram, corresponding to FIG. 2, schematically illustratingyet another embodiment of a nanofiber sheet of the present invention.

FIG. 8 is a schematic diagram for illustrating a method for using thenanofiber sheet illustrated in FIG. 1.

FIG. 9 is a perspective view illustrating an embodiment of a nano fibersheet manufacturing device usable in a nanofiber sheet manufacturingmethod of the present invention.

FIG. 10(a) is a plan view illustrating a deposit of nanofibers formed bya nanofiber sheet manufacturing method of the present invention, andFIG. 10(b) is a cross-sectional view taken along line II-II in the planview.

FIG. 11(a) is a plan view illustrating a first deposition region and asecond continuous deposition region formed respectively by first andsecond steps in a deposition step, and FIG. 11(b) is a cross-sectionalview taken along line III-III in the plan view.

FIG. 12 is a plan view illustrating movement paths for forming thenanofiber sheet illustrated in FIG. 1.

FIG. 13 is a diagram for illustrating conditions (1) and (2) inCalculation J3. FIG. 13(a) is a schematic diagram illustrating a statewherein condition (1) is not satisfied, FIG. 13(b) is a schematicdiagram illustrating a state wherein conditions (1) and (2) aresatisfied, and FIG. 13(c) is a schematic diagram illustrating a statewherein condition (1) is satisfied but condition (2) is not satisfied.

FIG. 14 is a flowchart illustrating an example of a process flow forcalculating the movement paths illustrated in FIG. 13.

FIG. 15 is a plan view illustrating another movement path for formingthe nanofiber sheet illustrated in FIG. 1.

FIG. 16 is a perspective view illustrating another embodiment of amanufacturing device for manufacturing a nanofiber sheet of the presentinvention.

FIG. 17 is a perspective view illustrating yet another embodiment of amanufacturing device for manufacturing a nanofiber sheet of the presentinvention.

FIG. 18 is a perspective view of a cartridge unit to be used in ananofiber sheet manufacturing device of the present invention.

FIG. 19 is an exploded perspective view of the cartridge unitillustrated in FIG. 18.

FIG. 20 is a perspective view illustrating yet another embodiment of ananofiber sheet manufacturing device of the present invention.

FIG. 21 is a perspective view illustrating yet another embodiment of ananofiber sheet manufacturing device of the present invention.

FIG. 22 is a graph illustrating a sectional contour curve of a nanofiberlayer according to a reference example.

FIG. 23 is a plan view illustrating an example of a method fordetermining a gradation region.

DESCRIPTION OF EMBODIMENTS

There are cases where, when a cosmetic sheet is attached to the skin,the sheet becomes visible. This makes the presence of the cosmetic sheetrecognizable. Particularly, applying a cosmetic, such as a foundation,onto the cosmetic sheet after attaching the sheet to the skin makes thecosmetic sheet stand out, which makes it difficult to obtain anatural-looking finish.

The cosmetic sheets of Patent Literatures 1 and 2 are visible whenattached to the skin, and are thus inadequate in terms ofnatural-looking finish. Patent Literatures 3 to 7 do not disclose anytechnique for making a nanofiber sheet less visible when attached to theskin.

The present invention therefore relates to nanofiber sheets, methods forusing the same, methods for manufacturing the same, and nanofiber sheetmanufacturing devices, capable of overcoming the drawbacks of theconventional art.

The present invention will be described below according to preferredembodiments thereof with reference to the drawings. FIGS. 1 to 3illustrate an embodiment of a nanofiber sheet of the present invention.

As illustrated in FIG. 1, a nanofiber sheet 10 includes a substratelayer 12, and a nanofiber layer 11 containing nanofibers of a polymercompound. The substrate layer 12 is located on one surface side of thenanofiber layer 11. In the present embodiment, the nanofiber layer 11and the substrate layer 12 are located adjacent to one another.

The nanofiber layer 11 in the nanofiber sheet 10 is a layer containingnanofibers of a polymer compound. Herein, a “nanofiber” typically has athickness of from 10 to 3000 nm, more preferably from 10 to 1000 nm, interms of equivalent circle diameter. The thickness of the nanofiber canbe measured, for example, with a scanning electron microscope (SEM) by:observing the fibers at a magnification of 10000×; discretionarilychoosing, from the two-dimensional image, 10 pieces of fibers, excludingdefected fibers (clumps of nanofibers, intersecting sections ofnanofibers, and polymer liquid droplets); and directly reading the fiberdiameter along a line orthogonal to the length direction of each fiber.

As illustrated in FIG. 2, the nanofiber layer 11 of the presentembodiment has a protuberance on the surface on the opposite side fromthe side of the substrate layer 12, whereas the nanofiber layer'ssurface facing the substrate layer 12 is flat. Hereinbelow, thenanofiber layer 11's surface on the opposite side from the side of thesubstrate layer 12 is referred to as “first surface S1” and thenanofiber layer's surface facing the substrate layer 12 is referred toas “second surface S2”. As illustrated in FIG. 2, the nanofiber layer 11of the present embodiment has a structure wherein the first surface S1side bulges toward the inner side. It should be noted that the nanofiberlayer 11 is actually extremely thin, but for the sake of explanation,the nanofiber layer 11 is illustrated extremely large in FIGS. 2 and 3.

A peripheral edge 17 of the nanofiber layer 11 constitutes the contourof the nanofiber layer 11 in a planar view, in the present embodiment,it is preferable that the thickness becomes the smallest at theperipheral edge 17 within the nanofiber layer 11.

In the nanofiber layer 11, the thickness D1 of the peripheral edge 17 isfrom 0.1 to 10 μm. In cases where the thickness D1 of the peripheraledge 17 varies depending on the position within the nanofiber layer 11,it is preferable that the minimum value and the maximum value of thethickness of the peripheral edge 17 are within the aforementioned range.

The thickness D1 (see FIG. 2) of the peripheral edge 17 is preferably0.3 μm or greater, more preferably 0.5 μm or greater, and 10 μm or less,preferably 9 μm or less, more preferably 8 μm or less, and preferablyfrom 0.3 to 9 μm, more preferably from 0.5 to 8 μm. The thickness D1 ofthe peripheral edge 17 can be measured according to the following“Method for Measuring Three-dimensional Shape of Nanofiber Layer”.

Method for Measuring Three-Dimensional Shape of Nanofiber Layer:

The thickness D1 of the peripheral edge 17 of the nanofiber layer 11 isfound by measuring the three-dimensional surface shape of the firstsurface of the nanofiber layer with a laser three-dimensional shapemeasurement system (e.g., a combination of Measurement SystemEMS2002AD-3D from COMS Co., Ltd. and Displacement Sensor LK-2000 fromKeyence Corporation). First, the nanofiber sheet is set by placing thesubstrate layer on the auto-stage. Next, the laser displacement meter isscanned while moving the auto-stage in the X-axis direction, to measurethe surface height of the first surface of the nanofiber layer at apredetermined measurement pitch X_(P). Then, the auto-stage is shiftedby a measurement pitch Y_(P) in the Y-axis direction orthogonal to theX-axis, and thereafter, the laser displacement meter is scanned whilemoving the auto-stage in the X-axis direction, to measure the surfaceheight of the first surface of the nanofiber layer at a predeterminedmeasurement pitch X_(P). This operation is repeated, to thereby obtainsurface shape data of the first surface of the nanofiber layer. Themeasurement pitch in the X-axis direction is set to 0.235 mm, themeasurement pitch Y_(P) in the Y-axis direction is set to 0.350 mm, andthe resolution in the height (Z-axis) direction is set to 0.1 μm. Themeasurement range is set to a range that includes the entire nanofiberlayer in a planar view—i.e., in the X-axis direction and Y-axisdirection. The measurement pitches may be changed as appropriatedepending on the measurement target. The aforementioned measurement isperformed under no-load. The thickness of the peripheral edge of thenanofiber layer is measured based on the measured three-dimensionalshape data. A method for measuring the thickness of the peripheral edgewill be described in further detail below. Unless specifically statedotherwise, “thickness” in the following description refers to a valuemeasured based on the three-dimensional shape data.

Method for Measuring Thickness of Peripheral Edge:

First, a planar contour outline indicating the contour shape of thenanofiber layer in a planar view is determined. The planar contouroutline may be obtained based on the three-dimensional shape data, ormay be obtained by observing the nanofiber layer under magnificationusing a microscope or the like. Typically, in a nanofiber layercontaining nanofibers, fibers will be sticking out from the surface, andsections with smaller or greater amounts of fibers will be formedlocally. Thus, noise may be included in a graph-more specifically, theplanar contour outline, later-described sectional contour outline, or80%-thickness isoline-obtained by position-by-position plotting ofmeasurement values, such as thicknesses, based on the three-dimensionalshape data. From the viewpoint of removing such noise, the planarcontour outline, sectional contour outline, or 80%-thickness isoline issubjected to a curve fitting process by polynomial approximation. Incases where the aforementioned process yields a plurality of approximatecurves, the approximate curve closest to the three-dimensional shapedata is selected. Next, a planar contour curve, which is obtained byapproximation (curve fitting) of the planar contour outline, isassociated with the three-dimensional shape data, to thereby determinethe peripheral edge of the nanofiber layer in the three-dimensionalshape data and measure the thickness of the peripheral edge.

More simply, the thickness D1 of the peripheral edge 17 of the nanofiberlayer 11 may be measured using a contact-type film-thickness meter(e.g., Litematic VL-50A, with a 5-mm-radius spherical carbide contactpoint, from Mitutoyo Corporation). The load to be applied to themeasurement target during measurement is set to 0.01 Pa.

The nanofiber layer 11 includes a gradation region G having a thicknessthat gradually increases inward from the peripheral edge 17. Thegradation region G is a region, including the peripheral edge 17 of thenanofiber layer 11, that protrudes from the peripheral edge 17 towardthe inner side. In a cross section taken along an orthogonal line thatis orthogonal to a central line CL of the contour of a later-describedinner region M when viewing the nanofiber layer 11's first surface S1 ina plan view, the gradation region G is a region that is inclined(sloped) toward the inner region M (see FIG. 2). Stated differently, thegradation region is a region where the surface of the nanofiber layer 11is inclined (sloped) in the aforementioned cross section. The “crosssection taken along an orthogonal line” is, for example, the crosssection taken along line II-II in FIG. 1. Such a cross section can befound based on the aforementioned three-dimensional shape data. A methodfor determining the gradation region will be described in detail below.

Method for Determining Gradation Region:

First, the position having the largest thickness in the aforementionedthree-dimensional shape data is determined as the apex position, and thethickness of the nanofiber layer at the apex position is obtained. Next,an isoline indicating a contour of a region where the thickness is 80%the thickness of the apex position (also referred to hereinafter as“80%-thickness isoline”) is determined based on the three-dimensionalshape data, and the positions on the isoline are reflected onto thethree-dimensional shape data, together with the aforementioned planarcontour curve. For example, as illustrated in FIG. 23, the planarcontour curve CO and the 80%-thickness isoline C80 are reflected ontothe three-dimensional shape data. Note that the 80%-thickness isolineused here has been subjected to the aforementioned curve fittingprocess. Next, an arbitrary position on the planar contour curve isdefined as the first point, and then ten points—i.e., first to tenthpoints-which divide the perimeter of the planar contour curve into tenequal parts are set cm the planar contour curve. The reference signs N1to N10 indicated in FIG. 23 are examples of the first to tenth points.Then, a sectional contour outline of the nanofiber layer in thethree-dimensional shape data is obtained at each of the first to tenthpoints. A “sectional contour outline” is a contour outline of across-sectional surface found when the nanofiber layer in thethree-dimensional shape data is cut along a line segment that connectseach of the first to tenth points, on the planar contour curve in aplanar view, to the 80%-thickness isoline with the shortest distance.The respective sectional contour outlines at each of the first to tenthpoints are subjected to the aforementioned curve fitting process, toobtain respective sectional contour curves. Next, for each obtainedsectional contour curve, the position of the corresponding one of thefirst to tenth points is reflected onto the sectional contour curve, todetermine the position of the nanofiber layer's peripheral edge on thesectional contour curve. Then, in each obtained sectional contour curve,an inclined region is determined, the inclined region having a width ofat least 3 mm and having a thickness that gradually increases inwardfrom the peripheral edge toward the inner side of the nanofiber layer.Here, the “width” refers to a length, in the sectional contour curve,from the peripheral edge to the apex position, or a length from theperipheral edge to the later-described maximum thickness portion.Examples of patterns according to which the thickness graduallyincreases along the sectional contour curve may include, patterns inwhich the thickness increases linearly; patterns in which the thicknessincreases along a curve, such as a sigmoid curve or an exponentialcurve; and patterns in which the thickness increases in multiple stages.Then, the number of points, among the first to tenth points, at whichthe corresponding sectional contour curve includes the aforementionedinclined region is counted. When the counted number of points at whichthe sectional contour curve includes the aforementioned inclined regionis defined as “n”, the percentage (%) of the number ofinclined-region-including sectional contour curves with respect to thetotal of ten points (first to tenth points) can be calculated from theexpression (n/10)×100(%). Stated differently, it is possible to assessthe percentage occupied by the gradation region within the entire lengthof the peripheral edge of the nanofiber layer. For example, if there arefive points, among the first to tenth points, at which the sectionalcontour curve includes the aforementioned inclined region, then it canbe assessed that the nanofiber layer being measured includes thegradation region in 50% of the entire length of the peripheral edge ofthe nanofiber layer.

Note that, unless specifically stated otherwise, the various dimensionsof the gradation region G and the inner region M—e.g., thelater-described maximum thickness portion 15's thickness, inclinationangle, etc., of the gradation region G—are arithmetic mean values ofmeasurement values found from the respective sectional contour curves atthe points including the aforementioned inclined region.

The nano fiber layer 11 of the present embodiment includes theaforementioned gradation region G and an inner region M surrounded bythe gradation region G. As illustrated in FIG. 2, in the nanofiber layer11 of the present embodiment, the thickness of the gradation region Ggradually increases in one direction, whereas the thickness in the innerregion M is substantially constant. The thickness of the inner region Mmay slightly vary depending on the position. For example, it ispermissible that the thickness varies within a range of around ±25% withrespect to the average thickness. In the present embodiment, thethickness of the inner region M is the same as the thickness D3 of themaximum thickness portion 15 of the gradation region G (see FIG. 2). The“maximum thickness portion 15 of the gradation region G” is the portionof the gradation region G where the thickness becomes the greatest, andis the inner end of the gradation region G, and is the end on the innerregion M side in the present embodiment. The inner region M is a regionwherein the thickness is preferably 80% or greater, more preferably 90%or greater, with respect to the thickness at the apex position of thenanofiber layer 11. The inner region M can be determined based on theaforementioned sectional contour curves. The nanofiber layer 11 mayinclude both the gradation region G and the inner region M as in thepresent embodiment, or may include only the gradation region between theperipheral edge and the apex position, without including an innerregion.

From the viewpoint of manufacturability and handleability, it ispreferable that the maximum length of the nanofiber layer 11 in a planarview is preferably 500 mm or less, more preferably 300 mm or less, evenmore preferably 150 mm or less. From the same viewpoint, it ispreferable that the maximum length of the nanofiber layer 11 in a planarview is preferably 10 mm or greater. “Maximum length” refers to themaximum length spanning the nanofiber layer 11 in a planar view.

From the viewpoint of further improving adhesiveness with which thenanofiber layer 11 adheres to the surface of an object, it is preferablethat, when the entire length of the peripheral edge of the nanofiberlayer 11 is defined as 100%, the total length of sections where thegradation region G exists within the entire length of the peripheraledge is preferably 60% or greater, more preferably 80% or greater, evenmore preferably 90% or greater, even more preferably 100%. From the sameviewpoint, it is preferable that the gradation region G exists over theentire length of the peripheral edge of the nanofiber layer 11.

For convenience of measurement, the percentage of the total length ofsections where tire gradation region G exists with respect to the entirelength of the peripheral edge of the nanofiber layer 11 can becalculated as the percentage (%) of the number of sectional contourcurves including the aforementioned inclined region with respect to thetotal of ten points (first to tenth points), as found in theaforementioned “Method for Determining Gradation Region.” For example,if there are six points at which the sectional contour curve includesthe aforementioned inclined region, then the total length of sectionswhere the gradation region G exists will be 60% with respect to theentire length of the peripheral edge of the nanofiber layer 11.

In a cross section along the thickness direction of the nanofiber sheet10, the width W2 (see FIG. 2) of the inner region M is 200 mm or less,preferably 150 mm or less. The width W2 of the inner region M is thedistance between the maximum thickness portions 15 of the gradationregion G in the aforementioned cross section. In the present embodiment,the nanofiber sheet 10 has an inner region M in the nanofiber layer 11,but the nanofiber sheet 10 does not have to include an inner region M.Stated differently, the distance W2 between the maximum thicknessportions 15 of the gradation region G in the aforementioned crosssection may be substantially 0 mm, and the nanofiber sheet 10 mayinclude only the gradation region having a thickness that graduallyincreases from the peripheral edge 17 toward the apex position. In thiscase, the maximum thickness portion, which is the inner end of thegradation region G, serves as the apex position.

In the nanofiber layer 11, the distance W1 between the peripheral edge17 and the maximum thickness portion IS of the gradation region G is atleast 3 mm. The distance W1 between the peripheral edge 17 and themaximum thickness portion 15 of the nanofiber layer is the separationdistance from the peripheral edge 17 to a portion of the gradationregion G where the thickness becomes the greatest, and is the width ofthe gradation region G. Stated differently, the nanofiber layer 11includes at least 3 mm of the gradation region G. In cases where thedistance W1 between the peripheral edge 17 and the maximum thicknessportion 15 of the nanofiber layer 11, or the distance W1 between theperipheral edge 17 and the apex position, varies depending on theposition along the peripheral edge of the nanofiber layer 11, theminimum length of the distance W1 may be at least 3 mm. As describedabove, the distance between the peripheral edge 17 and the apex positionin the nanofiber layer 11, or the distance between the peripheral edge17 and the maximum thickness portion 15, is also referred to as thewidth W1 of the gradation region G.

The nanofiber sheet 10 is used by peeling the substrate layer 12 andattaching the nanofiber layer 11 to an object, such as the skin.

In the nanofiber sheet 10, by setting the thickness of the peripheraledge of the nanofiber layer 11, including the gradation region G, withina range from 0.1 to 10 μm and setting the width W1 of the gradationregion G to 3 mm or greater, the outer edge of the nanofiber layer 11will be less conspicuous and the nanofiber layer 11 will be harder tovisually recognize in a state where the nanofiber layer is attached toan object such as the skin. By attaching the nanofiber layer 11 of sucha nanofiber sheet 10 to the skin, for example, spots and wrinkles on theskin can be concealed effectively, while making the presence of thenanofiber layer 11 hard to recognize. Further, even when a cosmetic,such as a foundation, is applied onto the nanofiber layer 11 attached tothe skin, the outer edge (peripheral edge) of the nanofiber layer 11will be less conspicuous, and a natural finish can be obtained, with anappearance conforming seamlessly to the skin.

In contrast, if a cosmetic sheet including a nanofiber layer with aconstant thickness is attached to the skin, the outer edge of thecosmetic sheet may stand out, and the presence of the cosmetic sheet maybecome easily recognizable. Further, when a cosmetic, such as afoundation, is applied onto the cosmetic sheet attached to the skin, theouter edge may become more conspicuous, and also, the cosmetic sheet maytake on a color (shade) different from the skin, thus making thecosmetic sheet easily recognizable. Moreover, reducing the maximumthickness of the nanofiber layer will make it difficult to achieve theeffect of concealing spots and wrinkles.

From the viewpoint of achieving the effect of concealing spots andwrinkles more reliably, it is preferable that the thickness D3 of themaximum thickness portion 15 in the gradation region G is preferably 5.1μm or greater, more preferably 10 μm or greater, and preferably 500 μmor less, more preferably 400 μm or less, even more preferably 100 μm orless, and preferably from 5.1 to 500 μm, more preferably from 10 to 400μm, even more preferably from 10 to 100 μm.

From the same viewpoint, it is preferable that the thickness at the apexposition of the nanofiber layer 11 is within the aforementionedpreferable range for the thickness D3 of the maximum thickness portion15.

As described above, the gradation region G is inclined in a crosssection along the thickness direction Z of the nanofiber sheet 10. Fromthe viewpoint of making the nanofiber layer 11 even less conspicuouswhen attached to the skin, it is preferable that the inclination angle θ(see FIG. 4) of the gradation region G is preferably 0.001° or greater,more preferably 0.002° or greater, and preferably 10° or less, morepreferably 8° or less, and preferably from 0.001° to 10°, morepreferably from 0.002° to 8°. The inclination angle θ of the gradationregion G is an inclination angle formed between a horizontal plane and avirtual straight line Lp connecting the peripheral edge 17 of thenanofiber layer and the maximum thickness portion 15 of the gradationregion G (see FIG. 4) in the aforementioned cross section taken alongthe orthogonal line. The inclination angle θ can be calculated from thethickness D3 of the maximum thickness portion IS of the gradation regionG, the width W1 of the gradation region G, and a difference D2 inthickness between the peripheral edge 17 of the nanofiber layer 11 andthe maximum thickness portion 15. The peripheral edge 17 and the maximumthickness portion 15 can be determined by the aforementioned “Method forMeasuring Thickness of Peripheral Edge” and “Method for DeterminingGradation Region.”

From the viewpoint of improving the effect of concealing spots andwrinkles on the skin and also making the nanofiber layer even lessconspicuous, it is preferable that the ratio (D3/D1) of the thickness D3(see FIG. 2) of the maximum thickness portion 15 of the gradation regionG to the thickness D1 of the peripheral edge 17 is preferably 5000 orless, more preferably 4000 or less. For example, the ratio is preferably50 or greater, more preferably 100 or greater. Further, the ratio ispreferably from 50 to 5000, more preferably from 100 to 4000.

From the same viewpoint, it is preferable that the ratio of thethickness at the apex position of the nanofiber layer 11 to thethickness D1 of the peripheral edge 17 is within the aforementionedpreferable range for the ratio D3/D1.

From the same viewpoint, it is preferable that the difference D2 (seeFIG. 2) in thickness between the peripheral edge 17 and the maximumthickness portion 15 of the gradation region G is preferably 5 μm orgreater, more preferably 10 μm or greater, and preferably 500 μm orless, more preferably 400 μm or less, and preferably from 5 to 500 μm,more preferably from 10 to 400 μm. The maximum thickness portion 15 ofthe gradation region G is the inner end of the gradation region—i.e.,the inner end of the aforementioned inclined region. The difference inthickness between the inner end of the gradation region G and theperipheral edge is equivalent to the difference D2 in thickness betweenthe peripheral edge 17 and the maximum thickness portion 15 of thegradation region G.

From the viewpoint of improving attachability of the nanofiber layer tothe skin, it is preferable that the planar-view shape of the nanofiberlayer 11 is: a shape including, in its contour, a plurality ofcurvilinear sections having different curvatures; a shape including, inits contour, a plurality of rectilinear sections; or a shape including,in its contour, both the curvilinear sections and the rectilinearsections. Examples of shapes including, in the contour, a plurality ofcurvilinear sections having different curvatures may include a shapelike an ellipse which includes a plurality of curvilinear sections withdifferent curvatures, or a shape in which a plurality of curvilinearsections with different curvatures are formed as projections anddepressions (see FIG. 1) in a planar view. Examples of shapes including,in the contour, a plurality of rectilinear sections may includepolygonal shapes, such as rectangular, triangular, square or hexagonal,an arrow shape, a star shape, or the like, in a planar view. Examples ofshapes including, in the contour, both curvilinear sections andrectilinear sections may include a sector shape, a tear shape, asemicircular shape, a heart shape, or the like. A nanofiber layer 11having such a shape can easily conform to complex shapes on the face orthe like, and can be attached easily.

From the viewpoint of further improving attachability, it is preferablethat the contour outline of the nanofiber layer 11 in a planar view is ashape wherein more than half the length, of the entire length of thecontour outline, is constituted by a curve. In this case, from theviewpoint of further improving conformability of the nanofiber layer 11to the surface of an object, it is preferable that the contour outlineof the nanofiber layer 11, in a planar view, is a shape whereincurvilinear sections occupy preferably at least 60%, more preferably atleast 70%, even more preferably at least 80%, of the entire length ofthe contour outline, and it is further preferable that the entire lengthof the contour outline is constituted by curves. The contour outline ofthe nanofiber layer 11 in a planar view can be determined from theplanar contour curve as described above in “Method for MeasuringThickness of Peripheral Edge.”

The substrate layer 12 is a layer that enables the nanofiber sheet tomaintain its shape retainability, and may be constituted by a singlelayer or a plurality of layers.

For the substrate layer 12, it is possible to use, for example, a filmmade of synthetic resin such as polyolefin resin or polyester resin, ora fiber sheet such as a nonwoven fabric. In cases of peelably layeringthe substrate layer 12 to the nanofiber layer 11, from the viewpoint ofimproving peelability, it is preferable to apply silicone resin, orapply a peeling treatment such as a corona discharge treatment, to thesurface of the film facing the nanofiber layer 11. Further, in cases ofusing a synthetic resin-made film etc. as the substrate layer 12, fromthe viewpoint of improving peelability, it is preferable to provide apowder or particle layer formed by sprinkling powder or particles on thesurface of the film.

In the nanofiber sheet 10 of the present embodiment, the nanofiber layer11 and the substrate layer 12 are integral before use; and at the timeof use, the nanofiber layer 11 and the substrate layer 12 are peeledapart to remove the substrate layer 12. From the viewpoint of improvingworkability for peeling the substrate layer 12 from the nanofiber layer11, it is preferable that the substrate layer 12 has air permeability.This allows air to enter between the nanofiber layer 11 and thesubstrate layer 12, which can make it easy to peel the nanofiber layer11 and the substrate layer 12.

For the substrate layer 12 having air permeability, it is preferable touse a fiber sheet or a sponge. More specifically, examples of fibersheets may include various types of nonwoven fabrics, woven fabrics,knitted fabrics, paper, mesh sheets, and laminates thereof. Examples ofusable nonwoven fabrics may include, although not limited to, meltblownnonwoven fabrics, spunbond nonwoven fabrics, air-through nonwovenfabrics, and spun-laced nonwoven fabrics. Fibers or strands constitutingthese nonwoven fabrics or mesh sheets may have a thickness in the orderof nanofibers, or may be thicker. For the fibers, it is possible to usefibers made from fiber-formable synthetic resin, or cellulose-basednatural fibers such as cotton or pulp. Examples of sponges mayspecifically include porous materials, e.g., foamed resin, made byfoaming synthetic resin or natural resin. Examples of usable syntheticresin and natural resin may include, although not limited to, urethane,polyethylene, melamine, natural rubber, chloroprene rubber, ethylenepropylene rubber, nitrile rubber, silicone rubber, and fluororubber. Forthe foamed resin, various materials can be used so long as anair-permeable structure can be formed.

From the viewpoint of facilitating adhesion of the nanofiber layer 11 tothe skin, it is preferable that the substrate layer 12 is a nonwovenfabric.

It is preferable that the substrate layer 12, when located adjacent tothe nanofiber layer 11, has, on its surface facing the nanofiber layer11, a plurality of depressions or projections each having a widthgreater than the fiber diameter of the nanofiber. This structure isadvantageous in improving workability at the time of peeling thesubstrate layer 12 from the nanofiber layer 11 in cases where thesubstrate layer 12 does not have air permeability.

The thickness of the substrate layer 12 is preferably 5 μm or greater,more preferably 10 μm or greater, and preferably 20 mm or less, morepreferably 15 mm or less, and preferably from 5 μm to 20 mm, morepreferably from 10 μm to 15 mm.

The nanofiber sheet 10 may be used in a state where the nanofiber layer11 contains a liquid substance such as cosmetic serum. In this case,from the viewpoint of preventing the nanofiber layer 11 from beingdissolved by the liquid substance such as cosmetic serum, it ispreferable that the nanofiber layer 11 is water-insoluble. Herein,“water-insoluble” refers to a property wherein, in an environment of 1atm. and 23° C., when 1 g of the nanofiber layer 11 is immersed in 10 gof ion-exchanged water, more than 0.5 g of the immersed nanofiber layer11 remains undissolved-more preferably, more than 0.8 g remainsundissolved-after 24 hours. Stated differently, “water-insoluble” refersto a property wherein, in an environment of 1 atm. and 23° C., when 1 gof the nanofiber layer 11 is immersed in 10 g of ion-exchanged water,less than 0.5 g of the immersed nanofiber layer 11 dissolves-morepreferably, less than 0.2 g dissolves-after 24 hours.

The nanofiber layer 11 is formed by depositing nanofibers containing afiber-formable polymer compound. From the viewpoint of making thenanofiber layer 11 water-insoluble, it is preferable that the nanofiberlayer 11 includes nanofibers of a water-insoluble polymer compound as afiber-formable polymer compound. With this construction, the shaperetainability of the nanofiber layer 11 can be maintained, even when thenanofiber layer is impregnated with a water-soluble component used in acosmetic. Examples of the water-insoluble polymer compound may includecompletely saponified polyvinyl alcohol that can be made insoluble afterformation of nanofibers, partially saponified polyvinyl alcohol that canbe cross-linked after formation of nanofibers when used in combinationwith a cross-linking agent, oxazoline-modified silicone such aspoly(N-propanoylethyleneimine)-graft-dimethylsiloxane/γ-aminopropylmethylsiloxanecopolymer, zein (primary component of corn protein), polylactic acid(PLA), polyester resins such as polyethylene terephthalate resins andpolybutylene terephthalate resins, polyacrylonitrile resins, acrylicresins such as polymethacrylate resins, polystyrene resins, polyvinylbutyral resins, polyurethane resins, polyamide resins such as nylon,polyimide resins, and polyamide imide resins. The water-insolublepolymer compound may be used singly, or two or more types may be used incombination.

The nanofiber layer 11 may contain nanofibers of a water-soluble polymercompound. Examples of the water-soluble polymer compound may include:natural polymers, e.g., pullulan, mucopolysaccharides such as hyaluronicacid, chondroitin sulfate, poly-γ-glutamic acid, modified corn starch,β-glucan, glucooligosaccharide, heparin, and keratosulfate, cellulose,pectin, xylan, lignin, glucomannan, galacturonic acid, psyllium seedgum, tamarind seed gum, gum arabic, tragacanth gum, water-solublesoybean polysaccharides, alginic acid, carrageenan, laminaran, agar(agarose), fucoidan, methyl cellulose, hydroxypropyl cellulose, andhydroxypropyl methylcellulose; and synthetic polymers, e.g., partiallysaponified polyvinyl alcohol (not used in combination with across-linking agent), low-saponification polyvinyl alcohol, polyvinylpyrrolidone (PVP), polyethylene oxide, water-soluble nylon,water-soluble polyester, and sodium polyacrylate. One type of thewater-soluble polymer compound may be used singly, or two or more typesmay be used in combination.

The nanofiber layer 11 may contain polymer compounds other than theaforementioned water-insoluble polymer compound and water-solublepolymer compound. Typical examples of other polymer compounds mayinclude polypropylene, polyethylene, polystyrene, polyvinyl alcohol,polyurethane, polyethylene oxide, polyethylene terephthalate,polybutylene terephthalate, polyethylene naphthalate, poly-m-phenyleneterephthalate, poly-p-phenylene isophthalate, polyvinylidene fluoride,polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylchloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile,polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate,polyester carbonate, nylon, aramid, polycaprolactone, polylactic acid,polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate,and polypeptide. The aforementioned polymer compound may be used singly,or a plurality of compounds may be used as a mixture.

In cases where the nanofiber layer 11 is rendered water-insoluble, thecontent of the water-insoluble polymer compound(s) contained in thenanofiber layer 11, with respect to the entire mass of the nanofiberlayer 11, is preferably greater than 50 mass %, more preferably 80 mass% or greater, and the content of the water-soluble polymer compound(s)contained in the nanofiber layer 11, with respect to the entire mass ofthe nanofiber layer 11, is preferably less than 50 mass %, morepreferably 20 mass % or less.

The nanofiber layer 11 may be constituted only by nanofibers, or maycontain other components in addition to nanofibers. Examples of othercomponents that can be used herein include components which aresubstances other than nanofibers and are used in cosmetics. Usableexamples may include medicinal components, moisturizing components,various vitamins, perfumes, anti-UV agents, surfactants, coloringpigments, body pigments, dyes, stabilizers, antiseptics, andantioxidants. One of the aforementioned components may be used singly,or two or more types may be used in combination.

In cases where the nanofiber layer 11 contains other components inaddition to nanofibers, the content of nanofibers occupying thenanofiber layer 11 is preferably from 40 to 95 mass %, more preferablyfrom 70 to 90 mass %.

The content of other components in the nanofiber layer 11 is preferablyfrom 5 to 60 mass %, more preferably from 10 to 30 mass %.

In cases where the nanofiber layer 11 is formed by nanofibers containingother components, such nanofibers can be prepared, for example, bycompletely dissolving the water-soluble polymer compound and the othercomponents in water and mixing the same in this state. As anotherexample, such nanofibers can be obtained by using nanofibers havinghollow sections, and including an emulsion of the other components inthose hollow sections. Depending on the type of reaction of the othercomponent(s), a single type of component may be included in thenanofibers, or two or more components may be included.

From the viewpoint of effectively concealing spots and wrinkles on theskin, it is preferable that the basis weight of the inner region M ofthe nanofiber layer 11 is 0.01 g/m² or greater, more preferably 0.1 g/m²or greater, and preferably 50 g/m² or less, more preferably 40 g/m² orless, and preferably from 0.01 to 50 g/m², more preferably from 0.1 to40 g/m². The basis weight of the inner region M of the nanofiber layer11 can be measured by: cutting out a 10 mm×10 mm measurement piece fromthe inner region M; measuring the mass of the measurement piece with ascale; and dividing the mass by the area (100 mm²) of the measurementpiece. From the same viewpoint, it is preferable that the basis weightat the apex position of the nanofiber layer 11 is within theaforementioned preferable range for the basis weight of the inner regionM.

In the foregoing embodiment, the thickness of the inner region M issubstantially constant over its entire region. However, the thickness ofthe inner region M may vary depending on the position, as illustrated inFIG. 5 and FIG. 6. In the embodiment illustrated in FIG. 5 and FIG. 6,the explanation on the nanofiber sheet of the foregoing embodimentapplies as appropriate, unless there are contradictions. The nanofibersheet 10 a illustrated in FIG. 5 includes a plurality of depressions 18respectively having different depths on the first surface S1 side of theinner region M. The thickness D5 (see FIG. 5) at the depression 18 ofthe inner region M is smaller than the thickness D3 at the maximumthickness portion 15 of the gradation region G. From the viewpoint ofimproving tight-adhesiveness of the nanofiber layer 11, it is preferablethat the thickness D5 (see FIG. 5) at the depression 18 of the innerregion M, with respect to the thickness D3 at the maximum thicknessportion 15, is preferably 50% or greater, more preferably 60% orgreater, and preferably 100% or less, more preferably 90% or less, andpreferably from 50 to 100%, more preferably from 60 to 90%.

From the viewpoint of improving the nanofiber layer 11's concealabilityof spots and wrinkles, it is preferable that the thickness D5 (see FIG.5) at the depression 18 of the inner region M is preferably 5.1 μm orgreater, more preferably 10 μm or greater, and preferably 500 μm orless, more preferably 400 μm or less, and preferably from 5.1 to 500 μm,more preferably from 10 to 400 μm. In cases where the thickness D5 atthe depression 18 of the inner region M varies for each depression 18,it is preferable that the minimum value of the thickness D5 at thedepression 18 of the inner region M is within the aforementioned range.

As in the nanofiber sheet 10 b illustrated in FIG. 6, the inner region Mmay include a depression 19 b forming a section having a smallerthickness than the maximum thickness portion 15 of the gradation regionG, in addition to a depression 19 a forming a section having a greaterthickness than the maximum thickness portion 15 of the gradation regionG. Hereinbelow, in the inner region M, the depression 19 a forming asection having a greater thickness than the maximum thickness portion 15of the gradation region G is also referred to as “shallow depression 19a,” and the depression 19 b forming a section having a smaller thicknessthan the maximum thickness portion 15 of the gradation region G is alsoreferred to as “deep depression 19 b.” In the inner region M, the deepdepression 19 b is formed along the peripheral edge of the inner regionM and more toward the outside than the shallow depressions 19 a.Further, in the inner region M, the thickness gradually increases inwardfrom the bottom portion of the deep depression 19 b. Stated differently,the nanofiber layer 11 in the embodiment illustrated in FIG. 6 includes:a gradation region G1 formed along the nanofiber layer's peripheraledge; and a gradation region G2 formed more inward than the gradationregion G1 and along the peripheral edge of the inner region M.

From the viewpoint of improving the nanofiber layer 11's concealabilityof spots and wrinkles, it is preferable that the thickness D7 (see FIG.6) at the shallow depression 19 a in the inner region M is preferably5.1 μm or greater, more preferably 10 μm or greater, and preferably 500μm or less, more preferably 400 μm or less, and preferably from 5.1 to500 μm, more preferably from 10 to 400 μm, on the premise that thethickness D7 is greater than the thickness D3 of the maximum thicknessportion 15 of the gradation region G. In cases where the thickness D7 ateach shallow depression 19 a in the inner region M varies for eachshallow depression, it is preferable that the minimum value of thethickness D7 is within the aforementioned range.

From the same viewpoint, it is preferable that the thickness D9 (seeFIG. 6) at the deep depression 19 b in the inner region M is preferably5.1 μm or greater, more preferably 10 μm or greater, and preferably 500μm or less, more preferably 400 μm or less, and preferably from 5.1 to500 μm, more preferably from 10 to 400 μm, on the premise that thethickness D9 at the deep depression 19 b is smaller than the thicknessD3 of the maximum thickness portion 15 and the thickness D7 of theshallow depression 19 a. In cases where the thickness D9 at each deepdepression 19 b in the inner region M varies for each deep depression,it is preferable that the minimum value of the thickness D9 is withinthe aforementioned range.

In cases where the nanofibers, i.e. fibers, are deposited directly onthe substrate layer, the nanofiber layer 11 will be located adjacent tothe substrate layer 12. However, the nanofiber layer 11 does not have tobe located adjacent to the substrate layer 12, and for example, asillustrated in FIG. 7 which will be described later, an adhesive layeradherable to the surface of an object may be interposed between thesubstrate layer 11 and the nanofiber layer 11.

From the viewpoint of easily attaching the nanofiber sheet to the skin,it is preferable that the nanofiber sheet includes an adhesive layer 13adherable to the surface of an object. The adhesive layer 13 is used forattaching the nanofiber layer 11 to an object such as the skin. Theadhesive layer 13 may be located between the substrate layer 12 and thenanofiber layer 11—i.e., on the second surface S2 side of the nanofiberlayer 11—or may be located on the nanofiber layer 11's surface oppositefrom the substrate layer 12—i.e., on the first surface S1 side of thenanofiber layer 11.

From the viewpoint of maintaining adhesive force of the adhesive layer13, it is preferable that the adhesive layer 13 is located on the secondsurface S2 side of the nanofiber layer 11, as illustrated in FIG. 7. Thenanofiber sheet 10 c illustrated in FIG. 7 is used by peeling betweenthe adhesive layer 13 and the substrate layer 12 and then attaching theadhesive layer 13 to the skin.

In cases where the adhesive layer 13 is located on the first surface S1side of the nanofiber layer 11, the nanofiber sheet is used by attachingthe adhesive layer 13 to the skin, with the substrate layer 12 beingpeeled from the nanofiber layer 11 either before or after attaching thenanofiber sheet to the skin.

Examples of adhesives that may be used for constituting the adhesivelayer 13 may include adhesives such as oxazoline-modified siliconeadhesives, acrylic resin adhesives, olefin resin adhesives, andsynthetic rubber adhesives. From the viewpoint of maintaining strongadhesive force, it is preferable to use an acrylic resin adhesive forthe adhesive constituting the adhesive layer 13.

The thickness of the adhesive in the adhesive layer 13 is notparticularly limited.

not limited thereto.

At the time of using the nanofiber sheet 10, the nanofiber layer 11 isplaced in contact with and attached to the surface of an object suchthat the nanofiber layer 11's first surface S1 or second surface S2faces the object's surface. For example, as illustrated in FIG. 8(a),the first surface S1 of the nano fiber layer 11 of the nanofiber sheet10 is attached to the skin. In this case, the surface on the side of thesubstrate layer 12 will be located on the opposite side from the skin.

In cases where the nanofiber sheet includes the aforementioned adhesivelayer, the adhesive layer is attached to the object's surface such thatthe nanofiber layer 11's surface on the side of the adhesive layer facesthe object's surface. Stated differently, in cases where the nanofibersheet includes an adhesive layer, the nanofiber layer 11 is attached tothe object's surface via the adhesive layer 13.

In the method for using the nanofiber sheet 10 illustrated in FIG. 8,after making the nanofiber layer 11 adhere to the object's surface, thesubstrate layer 12 is peeled and removed from the nanofiber layer 11 asillustrated in FIG. 8(b). Thus, as illustrated in FIG. 8(c), only thenanofiber layer 11 is attached to the object's surface.

It is preferable to place the nanofiber layer in contact with object'ssurface, and use the nanofiber layer in a slate moistened with a liquidsubstance. Herein, “in a moistened state” refers to a state where thenanofiber layer 11 is dampened (impregnated) with a liquid substance andthereby the nanofiber layer 11 is in a moist (damp) state.

“Liquid substance” refers to a substance that is in a liquid state at20° C. Examples of liquid substances may include liquids such as water,aqueous solutions and aqueous dispersions, gel-state substancesthickened by thickeners, oils and fats that are either liquid or solidat 20° C., oily agents containing at least 10 mass % of such oils/fats,and emulsions (O/W emulsions, W/O emulsions) containing theaforementioned oil/fat and a surfactant such as a nonionic surfactant.

In cases where the aforementioned liquid substance contains a polyolthat is liquid at 20° C., examples of the polyol may include one or moretypes selected from ethylene glycol, propylene glycol, 1,3-butane diol,dipropylene glycol, polyethylene glycol having a weight-averagemolecular weight of 2000 or less, glycerin, and diglycerin.

In cases where the aforementioned liquid substance contains an oil thatis liquid at 20° C., examples of the oil may include: one or more typesof hydrocarbon oils selected from liquid paraffin, squalane, squalene,n-octane, n-heptane, cyclohexane, light isoparaffin and liquidisoparaffin; one or more types of ester oils selected from esters oflinear or branched fatty acids and linear or branched alcohols orpolyols, such as octyldodecyl myristate, myristyl myristate, isocetylstearate, isocetyl isostearate, cetearyl isononanoate, diisobutyladipate, di-2-ethylhexyl sebacate, isopropyl myristate, isopropylpalmitate, diisostearyl malate, neopentyl glycol dicaprate and alkyl(C12-15) benzoate, and triglycerol fatty acid esters (triglycerides)such as caprylic/capric triglyceride; and one or more types of siliconeoils selected from dimethyl polysiloxane, dimethyl cyclopolysiloxane,methylphenyl polysiloxane, methylhydrogen polysiloxane and higheralcohol-modified organopolysiloxane. The aforementioned oil may be usedsingly, or two or more types may be used in combination.

In cases where the aforementioned liquid substance contains a fat thatis solid at 20° C., examples of the fat may include one or more typesselected from vaseline, cetanol, stearyl alcohol, and ceramide.

Methods for using the nanofiber layer 11 in a state moistened with theaforementioned liquid substance may include, for example: (1) a methodof making the nanofiber layer 11 adhere to the object's surface in astate where the object's surface is moistened with a liquid substance;(2) a method of moistening the nanofiber layer 11 with a liquidsubstance in a state where the nanofiber layer 11 is adhering to theobject's surface; and (3) a method of making the nanofiber layer 11adhere to the object's surface in a state where the nanofiber layer 11is moistened with a liquid substance. By moistening either the object'ssurface or the nanofiber layer's surface by applying a liquid substancebefore or after bringing the surface of the nanofiber layer 11 intocontact with the object's surface, the liquid substance gets supportedby the nanofiber layer or the liquid substance adheres to the surface ofthe fibers in the nanofiber layer, and thereby, the nanofiber layer 11becomes more transparent, which can make the peripheral edge 17 evenless conspicuous.

In the method (1), by bringing the nanofiber layer 11 into contact withthe object's surface moistened by applying a liquid substance, theliquid substance on the object's surface can be transferred to thenanofiber layer 11 by capillary action of the nanofiber layer 11.

In the aforementioned methods (1) to (3), in order to moisten thesurface of an object, or the nanofiber layer 11 attached to the object'ssurface, with a liquid substance, the liquid substance may simply beapplied or sprayed onto the surface. The liquid substance used forapplication or spraying may be a substance that includes a liquidcomponent at the temperature at which the nanofiber sheet 10 is attachedand that has a viscosity (viscosity measured with an E-type viscometer)of around 5000 mPa-s or less at that temperature. Examples of such aliquid substance may include water, aqueous solutions, ester oils,hydrocarbon oils and silicone oils that are liquid at 20° C., polyolsthat are liquid at 20° C. such as glycerin and propylene glycol, andaqueous dispersions containing one or more of the aforementionedcomponents. For the liquid substance, it is also possible to use, forexample, emulsions such as O/W emulsions, or aqueous liquids thickenedby various thickeners such as thickening polysaccharides.

As described above, in the method for using the nanofiber sheetaccording to the present embodiment, the nanofiber layer 11 is used bybeing attached to the surface of an object. This method of use aims atimproving the appearance of the object or the state of the surface byattaching the nanofiber layer 11 to the object's surface. For example,in cases where the skin is the object, the appearance of the skin can beimproved by attaching the nanofiber layer 11 to the skin to therebyconceal spots and wrinkles on the skin. Further, the surface state ofthe skin can be improved by attaching the nanofiber layer 11 to the skinto thereby improve the spreadability of foundation, i.e., thecondition/state of application of foundation.

Next, methods for manufacturing the nanofiber sheet of the presentinvention will be described according to preferred embodiments thereofwith reference to the drawings. FIG. 9 schematically illustrates anembodiment (first embodiment) of an electrospinning device used in amethod for manufacturing the nanofiber sheet illustrated in FIG. 1. Theelectrospinning device 100 illustrated in FIG. 9 includes: a nozzle 20configured to eject a material liquid; a counter electrode 30 configuredto create an electric field between the nozzle 20 and the counterelectrode; a collecting unit 40 configured to collect nanofibers (fibersF) produced from the material liquid; and a nozzle-moving mechanism 50configured to move the nozzle 20. “Material liquid” refers to a solutionor a dispersion liquid of a material resin for the nanofibers.

The electrospinning device 100 ejects a solution or a dispersion liquidof a material resin (also referred to collectively as “material liquid”hereinafter) from the nozzle 20, to thereby form small-diameter fibers Fby electrospinning. The nozzle 20 is mounted to a later-describednozzle-moving mechanism 50. The nozzle 20 is a member for ejecting amaterial liquid that is supplied from a material liquid supplying unit(not illustrated), and is in communication with the material liquidsupplying unit via a material liquid supplying path (not illustrated).The material liquid supplying unit is configured so as to be capable ofsupplying the material liquid to the nozzle 20 quantitatively by a knownmeans such as a pressure-loading device. The material liquid supplyingunit supplies the material liquid to the nozzle 20 either continuouslyor intermittently.

In the present embodiment, the nozzle 20 is made from anelectroconductive material such as metal, and is electrically connectedto a voltage application unit 32. More specifically, a positive ornegative voltage can be applied to the nozzle 20.

The counter electrode 30 is a member made from an electroconductivematerial such as metal, and is located in opposition to the nozzle 20.The counter electrode 30 is grounded, and thereby, an electric field canbe created between the nozzle 20 and the counter electrode 30. Thecounter electrode 30 may be electrically connected to a voltageapplication unit 32 such as a direct-current high-voltage power supply,so that voltage can be applied. In the present embodiment, the counterelectrode 30 also serves as a later-described collecting unit 40.

In this electrospinning device 100, a potential difference is createdbetween the nozzle 20 and the counter electrode 30 by applying apositive voltage to the nozzle 20, or by applying a negative voltage tothe counter electrode 30, or both. It is also preferable to create apotential difference between the nozzle 20 and the counter electrode 30by applying a negative voltage to the nozzle 20, or by applying apositive voltage to the counter electrode 30, or both. From theviewpoint of improving the electrification properties of the materialliquid, it is preferable that the potential difference applied betweenthe nozzle 20 and the counter electrode 30—i.e., the potentialdifference applied between the nozzle 20 and the collecting unit 40—ispreferably 1 kV or greater, more preferably 10 kV or greater, and, fromthe viewpoint of preventing discharge, the potential difference ispreferably 100 kV or less, more preferably 50 kV or less.

The collecting unit 40 is a member for collecting/accumulating fibers Fproduced by electrically stretching the material liquid. In the presentembodiment, the collecting unit 40 is located in opposition to thenozzle 20. The collecting unit 40 also serves as the aforementionedcounter electrode 30, and is grounded or electrically connected to thevoltage application unit 32, so that a voltage can be applied. Stateddifferently, in the present embodiment, an electric field can be createdbetween the nozzle 20 and the collecting unit 40.

The nozzle-moving mechanism 50 is configured so that it can make thenozzle 20 movable in a planar direction. In the present embodiment, thenozzle-moving mechanism 50 includes: a slider 51 configured to retainthe nozzle 20; and rails 53 and 55 extending respectively along theX-axis direction and Y-axis direction. The rail 53 moves on the rail 55,and the slider 51 moves on the rail 53. The nozzle-moving mechanism 50is electrically connected to a control unit (not illustrated). Based ondata about a movement path for the nozzle as inputted to the controlunit, or based on an operation signal inputted by an operator to thecontrol unit via a controller, the nozzle-moving mechanism 50 candeposit fibers F onto the collecting unit 40 while making the nozzle 20move. The control unit is configured such that data on a nozzle movementpath determined in a later-described path calculation step is inputtedor is inputtable to the control unit. Inputting of data on the movementpath to the control unit may be achieved by input via a storage mediumsuch as a USB memory, or by input via a network such as the Internet oran intranet.

In the present embodiment, the electrospinning device 100 includes astage 60 made from a non-electroconductive material. The collecting unit40, which is the counter electrode 30, is mounted on the stage 60. Thenozzle-moving mechanism 50 is capable of moving the nozzle 20 in theplanar direction within a range where the stage 60 is provided.

In a method for manufacturing a nanofiber sheet according to the presentembodiment, the electrospinning device 100 configured as above is usedto deposit, onto the collecting unit, fibers F produced from a materialliquid by electrospinning. In a state where an electric field is createdbetween the electric-field nozzle 20 and the counter electrode 30, amaterial liquid is supplied to the nozzle 20, and the material liquid isejected from the nozzle. At this time, the electrospinning device 100makes the nozzle 20 eject the material liquid while moving the nozzle 20with the nozzle-moving mechanism 50. At this time, the electrospinningdevice 100 makes the nozzle 20 eject the material liquid while movingthe nozzle 20 with the nozzle-moving mechanism 50. The ejected materialliquid is repeatedly subjected to electric repulsion and evaporation ofthe material liquid's solvent, and is thereby spun so as to be drawntoward the counter electrode 30 while forming fibers F. The nanofibersare deposited onto the collecting unit 40, which is also the counterelectrode 30, to thereby form a deposit of nanofibers (fibers F). Thisdeposit becomes the nanofiber layer 11.

In cases where the nanofiber layer 11 is configured such that the innerregion M has a large thickness and the gradation region G has athickness that gradually increases toward one direction as describedabove, from the viewpoint of easily forming the gradation region G, itis preferable to deposit the fibers F while moving the nozzle 20 in theplanar direction, and it is more preferable to deposit the fibers Fwhile moving the nozzle 20 in the planar direction such that the nozzle20 follows a predetermined circulating path. Examples may include:depositing the fibers F by moving the nozzle 20 such that the nozzlefollows paths in which deposition positions of the fibers F partiallyoverlap; or depositing the fibers F by moving the nozzle 20 whilevarying, at each of the deposition positions, the deposition time ordeposition amount for depositing the fibers F. In this way, thedeposition amount of the fibers F can be partially varied, therebyenabling the formation of a gradation region G having a depositionamount distribution wherein the deposition amount of the fibers Fgradually increases in one direction. Particularly, from the viewpointof forming the gradation region G efficiently, it is preferable todeposit the fibers F by moving the nozzle 20 while varying, at each ofthe deposition positions, the deposition time for depositing the fibersF. Instead of the nozzle 20, the counter electrode 30 may be moved inthe planar direction.

Below, a method for manufacturing a nanofiber sheet by depositing fibersF while moving the nozzle 20 will be described in detail according to apreferred embodiment thereof.

In the nanofiber sheet manufacturing method according to the presentembodiment, nanofibers (fibers F) are deposited onto the collecting unit40 while moving the nozzle 20, as described above. For example, when thenozzle 20 moves along the planar-view shape of the nanofiber sheet 10, afirst deposition region e1, which is constituted by a deposit ofnanofibers that is linear along the planar-view shape, is formed asillustrated in FIG. 10(a). The deposition amount of nanofibers ejectedfrom the nozzle tends to be greater at the center of the ejection holeof the nozzle 20 than on the outer edge side of the ejection hole. Thus,the deposit of nanofibers formed along the movement path of the nozzle20 will be formed such that its outer edge section has a region whosethickness gradually increases from the outer edge toward the center (seeFIG. 10(b)). Stated differently, with the nanofiber sheet manufacturingmethod of the present embodiment, it is possible to manufacture ananofiber sheet including a gradation region.

Further, by forming a deposit of nanofibers by moving the nozzle 20, thenanofibers will be deposited along the movement path of the nozzle 20.Thus, the planar-view shape of the deposit of nanofibers will have ashape conforming to the movement trajectory of the nozzle 20. Thus, itis possible to easily form a nanofiber layer 11 having a desiredplanar-view shape.

In the present embodiment, fibers F are deposited onto the collectingunit 40 while moving the nozzle 20, but according to the nanofiber sheetmanufacturing method of the present invention, the collecting unit 40onto which the fibers F are deposited may be moved, or both the nozzle20 and the collecting unit 40 may be moved. Forming a nanofiber layerwhile moving both the nozzle 20 and the collecting unit 40 isadvantageous in terms that the shape of the nanofiber layer can easilybe adjusted to an arbitrary shape. As described above, in the nanofibersheet manufacturing method of the present invention, fibers F aredeposited onto the collecting unit 40 while moving at least either thenozzle 20 or the collecting unit 40.

Examples of movement mechanisms for moving the collecting unit 40 mayinclude: a mechanism including a stage that holds the surface of thecollecting unit 40 opposite from the surface onto which nanofibers aredeposited, and a plurality of motors for moving the stage in the planardirection; or a collecting unit-moving mechanism 80 provided in anelectrospinning device 100A described further below.

In the nanofiber sheet manufacturing method of the present invention, adeposit of nanofibers is formed while moving at least either the nozzle20 or the collecting unit 40. Therefore, factors, such as the speed forejecting the material liquid from the nozzle 20 and the speed for movingat least either the nozzle 20 or the collecting unit 40, will affect thedeposition thickness of the nanofibers. So, the nanofiber sheetmanufacturing method of the present embodiment includes: a pathcalculation step for determining a movement path of the nozzle 20; and adeposition step for depositing nanofibers in accordance with themovement path. In this way, the thickness of the nanofiber layer can becontrolled accurately, and the gradation region G can be formed morereliably.

In the path calculation step, the movement path of the nozzle 20 isdetermined based on a correlation between factors relating to thedeposition distribution of nanofibers and the deposition thickness ofthe nanofibers. The movement path is for enabling formation of apredetermined nanofiber sheet. “Predetermined nanofiber sheet” is ananofiber sheet including a gradation region G, and having apredetermined planar-view shape and predetermined thickness.“Predetermined thickness” is a set value determined in accordance withproduct specifications etc., and may be the minimum thickness or maximumthickness of the nanofiber layer 11, or may be the minimum thickness ormaximum thickness of the gradation region G. From the viewpoint ofenabling concealment of wrinkles and spots and also facilitatingpenetration of functional agents, such as cosmetic serum, into the skin,it is preferable to set the minimum thickness D5 of the inner region Mas the predetermined thickness of the nanofiber sheet in cases where thenanofiber sheet includes an inner region M, and to set the thickness D3of the maximum thickness portion 15 of the gradation region G as thepredetermined thickness in cases where the nanofiber sheet does notinclude an inner region M. It should be noted that, although themovement path of the nozzle 20 is determined in the path calculationstep in the present embodiment, it is instead possible to determine themovement path(s) of either one, or both, of the nozzle 20 and thecollecting unit 40 in the path calculation step.

“Deposition distribution of nanofibers” is the distribution of thedeposition amount of nanofibers deposited on the collecting unit 40.Examples of factors relating to the deposition distribution ofnanofibers may include: the movement speed of the nozzle 20 or thecollecting unit 40; the ejection speed of the material liquid; thepotential difference between the nozzle 20 and the counter electrode 30;the distance between the nozzle 20 and the collecting unit 40; the innerdiameter of the nozzle 20; and the material of the nozzle. One or morefactors selected from the above may be used in combination. By adjustingthe values of each of the aforementioned factors, the thickness of thenanofiber layer can be increased/decreased. Among the aforementionedfactors relating to the deposition distribution of nanofibers, “thematerial of the nozzle” is a factor that affects the amount of charge ofthe nozzle 20.

The path calculation step will be described below according to anexample wherein the movement speed of the nozzle 20 (also referred tohereinafter as “Factor A”), the ejection speed of the material liquid(also referred to hereinafter as “Factor B”), and the distance betweenthe nozzle 20 and the collecting unit 40 (also referred to hereinafteras “Factor C”) are employed as the factors relating to the depositiondistribution of nanofibers. The movement speed of the nozzle 20 (FactorA) and the ejection speed of the material liquid (Factor B) serve toincrease/decrease the deposition amount of nanofibers per unit area,which in turn increases/decreases the deposition thickness of thenanofibers. The distance between the nozzle 20 and the collecting unit40 (Factor C) serves to increase/decrease the area of the deposit ofnanofibers per unit time. As can be understood, Factors A to C arefactors that cause changes in the deposition distribution of nanofibers.

The path calculation step involves finding a correlation between theFactors A to C and the thickness of the deposit of nanofibers. Thiscorrelation can be found, for example, by: setting the factors relatingto the deposition distribution of nanofibers to predetermined values;producing a test deposit of nanofibers by moving the nozzle 20 along apredetermined path; and measuring the thickness distribution of the testdeposit. For example, a test deposit of nanofibers is produced bysetting the Factors A to C to predetermined values and then moving thenozzle 20 in one direction as illustrated in FIG. 10, to acquire data onthe test deposit's thickness within a cross section taken in a directionorthogonal to the test deposit's extending direction (also referred tohereinafter as “simulation data”). The simulation data can be acquiredby measurements using, for example, a laser three-dimensional shapemeasurement system (e.g., a combination of Measurement SystemEMS2002AD-3D from COMS Co., Ltd. and Displacement Sensor LK-2000 fromKeyence Corporation). Based on the aforementioned simulation data andthe planar-view shape of the nanofiber layer 11 to be set, the formablenanofiber thickness is simulated, and the movement path is determined.As the simulation data, it is possible to use data with setting valuesof the aforementioned Factors A to C being set according to the samecondition, or to use a plurality of pieces of data with differentsetting values for the factors relating to the deposition distributionof nanofibers.

In the path calculation step, calculation is performed such that thepredetermined thickness of the nanofiber sheet takes on a set value byadjusting the setting values of the factors relating to the depositiondistribution of nanofibers (e.g., the aforementioned Factors A to C) orby providing the movement path with sections where the nanofiberdeposition positions either overlap or do not overlap. The calculatedmovement path will be a path along the planar-view shape of thenanofiber layer 11 set according to the product specifications etc., andthis path can be set, for example, by using software such as SELGenerator (from IAI Corporation). In the movement path calculation step,movement path calculation—i.e., movement path simulation—is repeateduntil it is possible to obtain a movement path that is along thenanofiber layer 11's planar-view shape to be set and that satisfiesconditions for giving the nanofiber thickness a predetermined value.

In the deposition step, nanofibers are deposited, while moving at leasteither the nozzle 20 or the collecting unit 40, in accordance with themovement path determined in the path calculation step. In theelectrospinning device 100 of the present embodiment, data on themovement path as determined in the path calculation step is transmittedto the control unit, and, based on an operation signal transmitted fromthe control unit, the nozzle-moving mechanism 50 is operated to therebymake the nozzle 20 move along the movement path. By making at leasteither the nozzle 20 or the collecting unit 40 move along the movementpath in this way, it is possible to form a nanofiber layer having theplanar-view shape and thickness as simulated at the time of setting themovement path.

In cases where the nanofiber sheet includes an inner region M, like thenanofiber sheet 10 illustrated in FIG. 2, it is preferable to calculatethe movement path in the path calculation step such that the minimumthickness of the inner region M becomes equal to or greater than apredetermined set value. The minimum thickness D5 of the inner region Mis the thickness at a portion of the inner region M having the smallestthickness (see FIG. 2). In this case, in the path calculation step, amovement path is determined such that the minimum thickness of the innerregion M takes on a desired set value and the nanofiber layer 11 takeson a desired planar-view shape.

Depending on the planar-view shape and/or area of the nanofiber layer 11to be set, sections where nanofiber deposition positions overlap oneanother may be provided on the movement path of at least either thenozzle 20 or the collecting unit 40. In such cases, from the viewpointof improving the precision of the thickness of the nanofiber layer 11,it is preferable to provide the deposition step with the following firstand second steps. In the first step, either one of the nozzle 20 or thecollecting unit 40 is moved along a first movement path r1 such that adeposited portion of the nanofibers forms a continuous first depositionregion e1. In the second step, either one of the nozzle 20 or thecollecting unit 40 is moved along a second movement path such that thedeposited portion of the nanofibers forms a second continuous depositionregion e2 having a portion, in the width direction, that continuouslyoverlaps a portion, in the width direction, of the first depositionregion e1 or of a previously-formed continuous deposition region (seeFIG. 11(a)). Depending on the planar-view shape or area of the nanofiberlayer 11, the deposition step may include one or a plurality of secondsteps.

The first and second steps will be described by employing the nanofibersheet manufacturing method of the present embodiment as an example. Thenano fiber sheet manufacturing method of the present embodiment includesthe aforementioned first and second steps. The first step of the presentembodiment forms a continuous first deposition region e1 in whichnanofibers have been deposited. The first deposition region e1 is formedby moving at least either the nozzle 20 or the collecting unit 40 alonga first movement path. The first deposition region, as well as thelater-described second continuous deposition region, has a pathdirection X along the movement path, and a width direction Y orthogonalto the path direction. In the present embodiment, the first depositionregion e1 forms a portion constituting the peripheral edge of thenanofiber layer 11. The first movement path r1 is located so as tosurround a plurality of second movement paths r2 described below.

The second step of the present embodiment forms a second continuousdeposition region e2 in which nanofibers have been deposited (see FIG.11(a)). The second continuous deposition region e2 is formed by movingat least either the nozzle 20 or the collecting unit 40 along a secondmovement path r2. The second continuous deposition region e2 is formedso as to continuously overlap the first deposition region e1 along themovement path, in a manner partially overlapping the first depositionregion e1 in the width direction Y. In the present embodiment, thesecond continuous deposition region e2 is formed within a regionsurrounded by the first deposition region e1, and a portion of thesecond continuous deposition region e2 on the peripheral edge side inthe width direction Y continuously overlaps an inner-side portion of thefirst deposition region e1 on the inner side along the path direction X(see FIGS. 11(a) and 11(b)). The present embodiment includes a pluralityof second steps, and the movement path calculation step calculatesinner-side paths s1 to s3 (see FIG. 12) surrounded by the first movementpath r1, as second movement paths r2 to be used for the respectivesecond steps. The inner-side paths s1 to s3 are movement paths forrespectively forming second continuous deposition regions. Moving eitherone of the nozzle 20 or the collecting unit 40 along these inner-sidepaths respectively forms first to third inner deposition regionssurrounded by the first deposition region. Hereinbelow, a region inwhich one deposition region overlaps another deposition region is alsoreferred to as an overlap region E (see FIG. 11(b)). Examples ofconfigurations of overlap regions E may include a region in which thefirst deposition region e1 overlaps the second continuous depositionregion e2, and a region in which the second continuous deposition regione2 overlaps another continuous deposition region.

From the viewpoint of forming the gradation region G more reliably, itis preferable that, in the width direction Y, the overlap region E islocated between the midpoint f1 of one deposition region and an outeredge f2 of that deposition region located on the side of anotherdeposition region, as illustrated in FIG. 11(b). It is also preferablethat the overlap region E is provided such that, in the width directionY, the midpoint f1 of that deposition region and the midpoint f3 of thesecond continuous deposition region e2 are both located within the rangeof the overlap region E. The midpoint f1 or D of a deposition region isa position that bisects (i.e., divides into two equal parts) the length,in the width direction Y, of the respective continuous depositionregion. In FIG. 11(b), the overlap region E is located between, in thewidth direction Y, the midpoint f1 of the first deposition region e1 andthe outer edge f2 thereof located on the side of the second continuousdeposition region e2. From the same viewpoint as described above, it ispreferable to calculate the second movement path r2 in the movement pathcalculation step such that the second continuous deposition regionpartially overlaps the first deposition region between the firstdeposition region's midpoint f1 and the first deposition region's outeredge 12 located on the side of the second continuous deposition region,or such that the midpoint f1 of the deposition region and the midpointf3 of the second continuous deposition region e2 are both located withinthe range of the overlap region E. Hereinbelow, calculation of thesecond movement path r2 according to the aforementioned method is alsoreferred to as Calculation J1. In cases where the deposition stepincludes a plurality of second steps, it is preferable to determine thesecond movement paths r2 to be used in the respective second steps byperforming Calculation J1 in the path calculation step.

As described above, the nanofiber layer 11 includes a gradation region Gin its outer edge portion. As regards the overlap region E wherein theouter edge portion of the first deposition region and the outer edgeportion of the second continuous deposition region overlap one anotherin the width direction, increasing the width W10 of the overlap region Ewill increase the thickness D10 of the overlap region E, and reducingthe width W10 of the overlap region E will reduce the thickness D10 ofthe overlap region E. In other words, by adjusting the width W10 of theoverlap region E, the minimum thickness D5 of the inner region M can beadjusted. In this case, it is preferable that, in the movement pathcalculation step, the second movement path r2 is calculated by adjustingthe width W10 of the overlap region E in a manner such that thethickness D10 of the overlap region E becomes equal to or greater than apredetermined thickness based on the design of the nanofiber layer11—e.g., such that the thickness D10 becomes equal to or greater thanthe design minimum thickness D5 of the inner region M. Hereinbelow,calculation of the second movement path r2 according to theaforementioned method is also referred to as Calculation J2. In caseswhere the deposition step includes a plurality of second steps, it ispreferable to determine the second movement paths r2 to be used in therespective second steps by performing Calculation J2 in the pathcalculation step. In the aforementioned Calculation J1 and CalculationJ2, a separation distance between the first movement path r1 and thesecond movement path r2 is calculated based on a degree of overlapbetween nanofiber deposited portions (see FIG. 11(b)).

From the viewpoint of securing the minimum thickness D5 of the innerregion M more reliably and improving the effect of concealing spots andwrinkles by attaching the nanofiber layer, it is preferable that thedimensions of the overlap region E are within the following ranges.

The thickness D10 (see FIG. 11(b)) of the overlap region in the widthdirection Y with respect to the minimum thickness D5 of the inner regionM is preferably 100% or greater, more preferably 125% or greater, andpreferably 250% or less, more preferably 200% or less, and preferablyfrom 100 to 250%, more preferably from 125 to 200%. The thickness D10 ofthe overlap region E in the width direction Y is the minimum thicknessin the overlap region E.

The thickness D10 (see FIG. 11(b)) of the overlap region E is preferably0.2 μm or greater, more preferably 1 μm or greater, and preferably 100μm or less, more preferably 10 μm or less, and preferably from 0.2 to100 μm, more preferably from 1 to 10 μm.

The overlap region's width W10 (see FIG. 11(b)) with respect to theseparation distance W11, in the width direction Y, between the midpointof one deposition region and the midpoint of another deposition regionis preferably 1% or greater, more preferably 5% or greater, andpreferably 90% or less, more preferably 80% or less, and preferably from1 to 90%, more preferably from 5 to 80%.

The overlap region's width W10 (see FIG. 11(b)) in the width direction Yis preferably 1 mm or greater, more preferably 4 mm or greater, andpreferably 80 mm or less, more preferably 60 mm or less, and preferablyfrom 1 to 80 mm, more preferably from 4 to 60 mm.

The aforementioned dimensions (width and thickness) of the overlapregion E can be set by using the aforementioned simulation data obtainedby the measurement using a laser three-dimensional shape measurementsystem (e.g., a combination of Measurement System EMS2002AD-3D from COMSCo., Ltd. and Displacement Sensor LK-2000 from Keyence Corporation). Forexample, in cases where it is assumed that two deposition regions are tooverlap one another with a predetermined width W10 in the widthdirection, the overlap region's thickness D10 can be calculated based ondeposition distribution data measured by scanning, in the widthdirection Y, each of the two deposition regions before being overlapped.Spreadsheet software may be used for this calculation.

In the present embodiment, the inner-side paths s1 to s3 are calculatedin the movement path calculation step such that each inner-side path s1to s3 can be formed within a range surrounded by a movement pathadjacent thereto on the outside. Stated differently, in the presentembodiment, a first inner-side path s1 is calculated within a rangesurrounded by the first movement path r1, a second inner-side path s2 iscalculated within a range surrounded by the first inner-side path s1,and a third inner-side path s3 is calculated within a range surroundedby the second inner-side path s2 (see FIG. 12). The movement pathcalculation step of the present embodiment calculates the inner-sidepaths s1 to s3 according to the aforementioned Calculations J1 and J2,and also Calculation J3 described below.

As regards the inner-side paths, the more inward each inner-side path islocated from the first deposition region e1, the more difficult itbecomes to form a circulating path having a similar shape to theplanar-view shape of the nanofiber layer 11. To address this, in thepresent embodiment, the third inner-side path s3 is formed as a linearpath extending in one direction. It is preferable that, in the movementpath calculation step, circulating paths, or non-circulating paths, arecalculated depending on the area and/or shape of the range in which themovement paths are to be set. Hereinbelow, calculation of the secondmovement path r2—i.e., calculation of the inner-side path—according tothe aforementioned method is also referred to as Calculation J3.

In the present embodiment, the Calculation J3 is performed as follows.

First, a region surrounded by a previously-determined movement path isdetermined. This previously-determined movement path is also referred toas a “determined path h”, and a region surrounded by the determined pathh is also referred to as a “determined-path inner region H”. InCalculation J3, assessment is made regarding whether or not it ispossible to render, inside the determined-path inner region H, acirculating movement path having a substantially similar shape to theplanar-view shape of the nanofiber layer 11 (also referred to as“similar path k” hereinafter). The similar path k corresponds to thedetermined path h forming the determined-path inner region H; thus, incases where a path line forming the similar path k can fit within thedetermined-path inner region H, it is judged that the similar path k canbe rendered. Stated differently, it is assessed whether or not a similarpath k can be arranged in a manner such that mutually correspondingsections in the determined path h and the similar path k are adjoinedadjacent to one another.

Particularly, in Calculation J3, when focusing on a section H1 in thedetermined-path inner region H, which is a section where portions h1 andh2 of the determined path h oppose one another, it is assessed whetheror not the determined path's portion h1 and a portion k1 of a similarpath k corresponding to the determined path's portion h1 can be adjoinedadjacent to one another within the section H1, and it is also assessedwhether or not the determined path h's other portion h2—which opposesthe determined path h's portion h1—and a portion k2 of the similar pathk corresponding to the determined path's other portion h2 can beadjoined adjacent to one another within the section H1. Hereinbelow, inthe aforementioned opposing section H1, a portion of the determined pathis also referred to as “portion h1”, another portion of the determinedpath opposing the portion h1 is also referred to as “portion h2”, aportion of a similar path corresponding to the portion h1 is referred toas “portion k1”, and another portion of a similar path corresponding tothe portion h2 is referred to as “portion k2” (see FIGS. 13(a) to13(c)).

Determination of a movement path in the aforementioned section H1wherein the portions h1 and h2 of the determined path oppose one anotheris performed, for example, according to the process illustrated in FIG.14. In the flow illustrated in FIG. 14, the following steps (1) to (3)are performed.

Step (1): In P1, it is assessed whether or not the following condition(1) is satisfied. If condition (1) is satisfied, P2 in step (2) isperformed as the next process. If condition (1) is not satisfied, it isdetermined that a similar path cannot be rendered within the section H1where the portions h1 and h2 of the determined path h oppose one another(see FIG. 13(a)). Further, if condition (1) is not satisfied, it isdetermined that a later-described non-circulating path cannot berendered either.

Condition (1): Portion k1 of the similar path k is located on the innerside of portion h2 of the determined path, and also, the other portionk2 of the similar path is located on the inner side of the other portionh1 of the determined path.

Step (2): In P2, it is assessed whether or not the following condition(2) is satisfied. If condition (2) is satisfied, it is determined that asimilar path can be rendered within the section H1 where the portions h1and h2 of the determined path oppose one another (see FIG. 13(b)), andthe similar path is determined (P2-1 illustrated in FIG. 14). Ifcondition (2) is not satisfied, P3 in step (3) is performed as the nextprocess.

Condition (2): Portion k1 of the similar path is located adjacent toportion h1 of the determined path, and also, the other portion k2 of thesimilar path is located adjacent to the other portion h2 of thedetermined path.

An example of a state where the aforementioned condition (2) is notsatisfied may be a case where the portion k1 of the similar path islocated adjacent to the other portion h2 of the determined path, and theother portion k2 of the similar path is located adjacent to the portionh1 of the determined path (see FIG. 13(c)).

If the condition (2) is not satisfied, then in step (3) P3, a centralline CL1 that bisects (divides into two equal parts) the separationdistance between the similar path's portion k1 and the other portion k2in the width direction Y is determined as a movement path. Differentfrom similar paths, the central line CL1 is a non-circulating path.

The aforementioned Calculation J3 may be performed repeatedly dependingon the planar-view shape and thickness of the nanofiber sheet. From theviewpoint of improving the accuracy for adjusting the thickness of thenanofiber layer, it is preferable that the Calculation J3 is performedfor each section H1 where the portions h1 and h2 of the determined pathoppose one another.

In the nanofiber sheet manufacturing method of the present embodiment,the first to third inner-side paths s1, s2 and s3 are calculatedaccording to the aforementioned Calculations J1, J2 and J3 in the pathcalculation step. More specifically, the separation distance betweenadjacent paths is calculated by Calculations J1 and J2, and, based onthe separation distance, the first to third inner-side paths s1, s2 ands3 are calculated by Calculation J3. In this way, the nanofiber sheetmanufacturing method may determine movement paths by Calculation J1,Calculation J2, Calculation J3, or a combination of two or more of theabove calculations.

In the nanofiber sheet manufacturing method of the present embodiment, aplurality of movement paths is determined in the path calculation step,and the nozzle 20 is moved along the plurality of movement paths in thedeposition step. In the present embodiment, the movement path Ob is acombination of a path group that includes, in a nested manner, aplurality of circulating paths substantially similar to one another, anda crossover line path that connects the plurality of paths constitutingthe path group (see FIG. 12). As illustrated in FIG. 12, the path groupis constituted by the first movement path located on the outermost side,and the first to third inner-side paths s1 to s3 located on the innerside of the first movement path, and a crossover line path t connectsthese paths. From the viewpoint of forming the gradation region G moreaccurately, it is preferable that the plurality of circulating pathsconstituting the path group in the movement path are connected to thecrossover line path t. The crossover line path t connects the pluralityof circulating paths; the crossover line path may intersect with or bein contact with each of the circulating paths.

The crossover line path t may be a rectilinear path that connects theplurality of circulating paths constituting the path group.Incidentally, in the present electrospinning device 100, it ispreferable to eject the material liquid continuously from the viewpointof facilitating control of the ejection speed of the material liquid.So, in this case, from the viewpoint of suppressing the thickness of thenanofiber layer from increasing excessively, it is preferable to formthe crossover line path t as a rectilinear path that connects therespective termination points of the circulating paths constituting thepath group. Stated differently, it is preferable that, in the pathcalculation step, calculation is performed such that the crossover linepath t becomes a rectilinear path that connects the respectivetermination points of the circulating paths constituting the path group.

In calculating the movement path Ob, the movement path Ob may beconstituted by paths that move from the outside toward the inside, ormay be constituted by paths that move from the inside toward theoutside, or may be a combination of paths that move from the outsidetoward the inside and paths that move from the inside toward theoutside. The movement path Ob may be constituted by paths oriented in asingle movement direction, or may be a combination of paths oriented indifferent movement directions. In calculating the movement path Obillustrated in FIG. 12, an example of a configuration for moving fromthe outside toward the inside may be a configuration that moves in thefollowing order: the first movement path r1, the first inner-side paths1, the second inner-side path s2, and the third inner-side path s3. Anexample of a configuration for moving from the inside toward the outsidemay be a configuration that moves in the following order: the thirdinner-side path s3, the second inner-side path s2, the first inner-sidepath s1, and the first movement path r1.

Hereinbelow, the first movement path constituting the movement path Obmay be also referred to simply as r1, and the first to third inner-sidepaths located inside the first movement path may be also referred tosimply as s1 to s3, respectively.

From the viewpoint of improving the accuracy of the thickness of thenanofiber layer 11 and from the viewpoint of forming the gradationregion G more reliably, it is preferable that, in the deposition step,nanofibers are deposited while at least either the nozzle or thecollecting unit moves repeatedly along at least a portion of the path(s)constituting the path group. For example, in the case of the movementpath Ob illustrated in FIG. 12, at least either the nozzle or thecollecting unit repeats, a plurality of times, the operation of movingalong either one of the plurality of circulating paths r1, s1-s3. Inthis case, an operation of moving along the same path may be repeated aplurality of times before migrating to the movement along another path.Alternatively, an operation of moving along each path, once for eachpath, may be repeated a plurality of times. The aforementioned “samepath” may refer to each of the circulating paths r1, s1, s2, or mayrefer to the non-circulating path s3. In the case of the movement pathOb illustrated in FIG. 12, r1 may be performed once, s1 may be repeatedtwice, s2 may be repeated three times, and s3 may be repeated threetimes. Alternatively, each of the paths from r1 to s3 may be performedonce, and then, each of the paths from s1 to s3 may be performed once,and then, each of the paths s2 and s3 may be performed once.

From the same viewpoint, it is preferable that the path calculation stepcalculates the number of times of repetitions according to which atleast either the nozzle or the collecting unit repeats the movementalong the same path, such that the thickness of the nanofiber layertakes on a predetermined set value—e.g., the thickness of the nanofiberlayer becomes equal to or greater than the design minimum thickness D5of the inner region M. Hereinbelow, this calculation is also referred toas Calculation J4. Calculation J4 calculates, for each movement path,the number of times to repeat movement along each path, such that thethickness at a predetermined position in the nanofiber layer 11 becomesa preset thickness—e.g., the thickness of the nanofiber layer becomesequal to or greater than the design minimum thickness D5 of the innerregion M. Calculation J4 is effective in cases where the upper limit ofthe thickness of the overlap region E as calculated by theaforementioned Calculation J2 does not become equal to or greater than apredetermined design thickness.

In the deposition step, at least either the nozzle or the collectingunit may repeat movement along the same circulating path, or may movealong each of a plurality of circulating paths having substantiallysimilar shapes, as described above.

The movement path Ob of the present embodiment is constituted by acombination of a path group and a crossover line. However, asillustrated in FIG. 15, the movement path Ob1 may be a linear shape thatcan be rendered in one stroke. “A linear shape that can be rendered inone stroke” refers to a shape consisting of a single continuous line,wherein the line has no overlapping section. With this configuration,the material liquid can be ejected continuously, and ejection of thematerial liquid can be controlled even further. An example of a movementpath having a linear shape that can be rendered in one stroke may be aspiral shape as illustrated in FIG. 15.

The movement path Ob1 having a linear shape that can be rendered in onestroke can be calculated by the movement path calculation step using theaforementioned Calculations J1, J2 and J3. In the spiral-shaped movementpath illustrated in FIG. 15, the outermost path line corresponds to thefirst movement path r1, and path lines located inside the outermost pathline correspond to the first to third inner-side paths s1 to s3.

In calculating the movement path Ob1 having a linear shape that can berendered in one stroke, the movement path Ob1 may be a path moving fromthe outside toward the inside, or may be a path moving from the insidetoward the outside. Of the endpoints of the movement path Ob1illustrated in FIG. 15, when the endpoint on the first movement path r1side is defined as i1 and the endpoint on the third inner-side path s3side is defined as i2, the movement path Ob1 may be a path starting fromi1 as the start point and moving to i2 as the termination point, or maybe a path starting from i2 as the start point and moving to i1 as thetermination point.

From the viewpoint of improving the accuracy of the thickness of thenanofiber layer 11 and forming the gradation region G more reliably, itis preferable that, in the deposition step, at least either the nozzleor the collecting unit repeats movement along the movement path Ob1having a linear shape that can be rendered in one stroke. For example,in cases where at least either the nozzle or the collecting unit movesalong the movement path Ob1 illustrated in FIG. 15, the nozzle and/orthe collecting unit may start from the endpoint i1 and move from thefirst movement path r1 to the endpoint i2 on the third inner-side paths3 side, and may then move from the first inner-side path s1 via thesecond inner-side path s2 up to the endpoint i2 on the third inner-sidepath s3 side, and may then further move from the second inner-side paths2 up to the endpoint i2 on the third inner-side path s3 side.

From the viewpoint of suppressing fluctuations in the ejection area ofnanofibers ejected from the ejection hole of the nozzle 20 and formingthe gradation region G accurately, it is preferable to move either one,or both, of the nozzle 20 and the collecting unit 40 at a constantspeed. From the same viewpoint, the movement speed of either one of thenozzle 20 or the collecting unit 40 is preferably 5 mm/second orgreater, more preferably 50 mm/second or greater, and preferably 1000mm/second or less, more preferably 150 mm/second or less, and preferablyfrom 5 to 1000 mm/second, more preferably from 50 to 150 mm/second.

As illustrated in FIG. 1, the nano fiber sheet 10 of the presentembodiment includes a substrate layer 12 and a nanofiber layer 11containing nanofibers. The substrate layer 12 is located on one surfaceside of the nanofiber layer 11. Such a nanofiber sheet 10 including asubstrate layer 12 can be manufactured by arranging the substrate layer12 on the collecting unit 40, and depositing the nanofibers on thesubstrate layer 12. Further, from the viewpoint of shaping the nanofibersheet, after deposition of the nanofibers, into a desired shape andsize, it is preferable that the nanofiber sheet manufacturing methodincludes a cutting step of cutting the obtained nanofiber sheet 10, thesubstrate layer 12, or both the nanofiber sheet and the substrate layer.For the cutting step, it is possible to use, for example: a cuttingdevice including a cutter roller having, on the roller's circumferentialsurface, a cutting blade extending in the circumferential direction, andan anvil roller for receiving the blade on the cutter roller, or a knowncutting device such as an ultrasonic cutter.

The horizontal sectional shape of the ejection hole of the nozzle 20 isnot particularly limited, and may be formed in an arbitrary shape, suchas a circular planar shape or a shape with an acute angle. In caseswhere the nozzle 20 has a circular cylindrical shape as illustrated inFIG. 9, from the viewpoint of depositing fibers F efficiently, it ispreferable that the diameter at the tip end of the nozzle 20—i.e., thediameter of the ejection hole—is preferably from 0.1 to 20 mm, morepreferably from 0.1 to 15 mm.

A supplying end of the material liquid supplying path is preferablyarranged in the vicinity of the nozzle 20, and, for example, ispreferably arranged within a range within 10 mm from the nozzle 20.

From the viewpoint of easily forming the gradation region G, theseparation distance between the tip end of the nozzle 20 and the counterelectrode 30 in the electrospinning device 100 may preferably be 30 mmor greater, more preferably 50 mm or greater, and may preferably be 350mm or less, more preferably 300 mm or less.

Next, other embodiments of electrospinning devices usable in nanofibersheet manufacturing methods will be described with reference to FIGS. 16to 21. As regards electrospinning devices 100A, 100B, 100C, 100Daccording to the following second to fifth embodiments, features thatare different from the electrospinning device 100 of the foregoing firstembodiment will be described below. Features that are not particularlyexplained are the same as those in the electrospinning device accordingto the foregoing first embodiment, and the explanation on theaforementioned electrospinning device is applicable as appropriate.

FIG. 16 illustrates a second embodiment of an electrospinning device.The electrospinning device 100A illustrated in FIG. 16 includes: anozzle 20 configured to eject a material liquid; a voltage applicationtaut 32 serving as a power supply configured to apply a voltage to thenozzle 20; a collecting unit 40 configured to collect fibers F(nanofibers) produced from the material liquid; a nozzle-movingmechanism 50 configured to move the nozzle 20; and a cutting unit 7configured to cut the nanofiber sheet into a predetermined contourshape. In the present embodiment, the collecting unit 40 is constitutedby an electroconductive material such as metal. The collecting unit 40is located in opposition to the nozzle 20. The collecting unit 40 isgrounded. Thus, applying a positive or negative voltage to the nozzle 20will create an electric field between the nozzle 20 and the collectingunit 40.

The cutting unit 7 is for cutting the nanofiber sheet 10 formed on thecollecting unit 40 into a predetermined contour shape. The cutting unit7 is mounted to a later-described cutting unit-moving mechanism 70.Examples of the cutting unit 7 may include laser processing machinesthat perform melting-and-cutting by irradiation with a laser beam, andultrasonic cutters that perform melting-and-cutting by frictional heatcaused by ultrasonic vibrations. Herein, a laser processing machine canpreferably be used from the viewpoint of enabling cutting into finedetails shapes while being compact in size.

In cases of using a laser processing machine as the cutting unit 7,examples of lasers emitting laser beams may include CO₂ lasers, excimerlasers, argon lasers, semiconductor lasers, and YAG lasers. From theviewpoint of cutting the nanofiber sheet efficiently, it is preferableto use a CO₂ laser. The laser beam output is preferably 1.5 W or higher,more preferably 5 W or higher, and 150 W or lower, more preferably 50 Wor lower. The laser beam irradiation time is preferably 1 mm/second orgreater, more preferably 20 mm/second or greater, and preferably 1200mm/second or less, more preferably 300 mm/second or less.

It is preferable that the collecting unit 40 is made from anair-permeable member from the viewpoint of preventing burning of thenanofiber layer's surface facing the substrate layer at the time ofcutting the nanofiber sheet 10 by irradiation with a laser beam.

The electrospinning device 100A includes a base 90. The base 90 may bemade from a non-electroconduclive material or an electroconductivematerial. The base 90 has a longitudinal direction which is the X-axisdirection in a planar view, and a lateral direction which is the Y-axisdirection orthogonal to the X-axis direction. The principal surface ofthe base 90 consisting of the X-axis direction and the Y-axis directionis in opposition to the nozzle 20. As illustrated in FIG. 16, acollecting unit-moving mechanism 80 is placed in a central portion ofthe principal surface of the base 90. The nozzle-moving mechanism 50 anda cutting unit-moving mechanism 70 are arranged in peripheral edgeportions of the base 90 at positions so as not to interfere with oneanother.

The collecting unit-moving mechanism 80 includes an X-axis rail 84extending in the X-axis direction and a Y-axis rail 86 extending in theY-axis direction. The X-axis rail 84 has a depressed-shape guide groove83 formed along the X-axis direction. The Y-axis rail 86 has adepressed-shape guide groove 85 formed along the Y-axis direction. Thecollecting unit 40 is attached to the X-axis rail 84 in an electricallyinsulated state. The collecting unit 40 is slidable along the guidegroove 83 in the X-axis direction. The X-axis rail 84 is attached to theY-axis rail 86 in an electrically insulated state. The X-axis rail 84 isslidable along the guide groove 85 in the Y-axis direction. The Y-axisrail 86 is placed and fixed on the principal surface of the base 90 soas to pass along the base 90's center position in the X-axis direction.The collecting plane of the collecting unit 40 is parallel to theprincipal surface of the base 90. According to the collectingunit-moving mechanism 80 configured as above, the collecting unit 40 canmove freely within its collecting plane in the X-axis direction andY-axis direction.

The nozzle-moving mechanism 50 is configured so as to be able to movethe nozzle 20 at least within a range in which the collecting unit 40 ismovable. The nozzle-moving mechanism 50 includes: a slider 51 configuredto retain the nozzle 20; X-axis rails 53 and 55 extending respectivelyalong the X-axis direction and Y-axis direction; and a Z-axis rail 52extending in the Z-axis direction which is the vertical directionorthogonal to the X-axis direction and Y-axis direction. The Z-axis rail52 has a guide groove 57 formed in a depressed-shape along the Z-axisdirection. The slider 51 is fitted in the guide groove 57, and isslidable along the guide groove 57 in the Z-axis direction. The Y-axisrail 55 has a Y-axis guide groove 56 extending in the Y-axis direction.The X-axis rail 53 has an X-axis guide groove 54 extending in the X-axisdirection. The Z-axis rail 52 is attached to the Y-axis rail 55 in anelectrically insulated state. The Z-axis rail 52 is slidable along theY-axis guide groove 56 in the Y-axis direction. The Y-axis rail 55 isattached to the X-axis rail 53 in an electrically insulated state. TheY-axis rail 55 is slidable along the X-axis guide groove 54 in theX-axis direction. One end of the X-axis rail 53 is fixed to a supportcolumn 59 provided so as to stand on the principal surface of the base90. According to the nozzle-moving mechanism 50 configured as above, thenozzle 20 can move freely in the X-axis direction, the Y-axis direction,and the Z-axis direction.

The cutting unit-moving mechanism 70 is configured so as to be able tomove the cutting unit 7 at least within a range in which the collectingunit 40 is movable. The cutting unit-moving mechanism 70 includes: aslider 71 configured to retain the cutting unit 7; a Y-axis rail 73 andan X-axis rail 75 extending respectively along the Y-axis direction andX-axis direction; and a Z-axis rail 72 extending in the Z-axis directionwhich is the vertical direction orthogonal to the X-axis direction andY-axis direction. The Z-axis rail 72 has a guide groove 77 formed in adepressed-shape along the Z-axis direction. The slider 71 is fitted inthe guide groove 77, and is slidable along the guide groove 77 in theZ-axis direction. The Y-axis rail 73 has a Y-axis guide groove 74extending in the Y-axis direction. The X-axis rail 75 has an X-axisguide groove 76 extending in the X-axis direction. The Z-axis rail 72 isattached to the Y-axis rail 73 in an electrically insulated state. TheZ-axis rail 72 is slidable along the Y-axis guide groove 74 in theY-axis direction. The Y-axis rail 73 is attached to the X-axis rail 75in an electrically insulated state. The Y-axis rail 73 is slidable alongthe X-axis guide groove 76 in the X-axis direction. One end of theX-axis rail 75 is fixed to a support column 79 provided so as to standon the principal surface of the base 90. According to the cuttingunit-moving mechanism 70 configured as above, the cutting unit 7 canmove freely in the X-axis direction, the Y-axis direction, and theZ-axis direction.

The collecting unit-moving mechanism 80, the nozzle-moving mechanism 50,and the cutting unit-moving mechanism 70 are electrically connected to acontrol unit (not illustrated). Based on data about a movement path asinputted to the control unit, and/or based on an operation signalinputted by an operator to the control unit via a controller, thecollecting unit 40, the nozzle 20, and the cutting unit 7 can be moved.The control unit is configured such that data on a movement path isinputted or is inputtable to the control unit. Inputting of data on themovement path to the control unit may be achieved by input via a storagemedium such as a USB memory, or by input via a network such as theInternet or an intranet.

In the electrospinning device 100A of the present embodiment, thesupport column 59 of the nozzle-moving mechanism 50 and the supportcolumn 79 of the cutting unit-moving mechanism 70 are supported by thebase 90, which serves as a common support. Stated differently, thenozzle-moving mechanism 50 and the cutting unit 7 are supported by acommon support. As a result, the electrospinning device 100A includes,in a single device: a manufacturing unit configured to manufacture thenanofiber sheet 10 by depositing fibers F on the collecting unit 40while moving the nozzle 20 freely in biaxial directions by thenozzle-moving mechanism 50; and a cutting unit configured to cut thenanofiber sheet 10 into a predetermined contour shape while moving thecutting unit 7 freely in triaxial directions by the cutting unit-movingmechanism 70. Thus, the electrospinning device 100A of the presentembodiment is compact as a whole. By taking advantage of this compactconfiguration, the electrospinning device 100A of the present embodimentcan, for example, be easily installed at a counter of a store sellingnanofiber sheets, and provide, on site, nanofiber sheets with desiredcontour shapes in accordance with the customers' requests.

“The nozzle-moving mechanism 50 and the cutting unit 7 are supported bya common support” means that the nozzle-moving mechanism 50 and thecutting unit 7 are mounted to the support in a manner that, by movingthe support, the nozzle-moving mechanism 50 and the cutting unit 7 arealso moved simultaneously. In this sense, the nozzle-moving mechanism 50and the cutting unit 7 are not supported by a common support in caseswhere only one of the nozzle-moving mechanism 50 or the cutting unit 7is moved when the support is moved, and the other does not move.

A preferred embodiment of a method for manufacturing a nanofiber sheet10 by using the electrospinning device 100A will be described accordingto an example of manufacturing a nanofiber sheet including a nanofiberlayer and a substrate layer. First, a substrate layer is arranged on thecollecting unit 40. Then, based on an operation signal transmitted fromthe control unit (not illustrated), the collecting unit-moving mechanism80 is operated, to move the collecting unit 40 to a predeterminedposition. Next, in a state where an electric field is created betweenthe nozzle 20 and the collecting unit 40, a material liquid is suppliedto the nozzle 20, and the material liquid is ejected from the nozzle.While ejecting the material liquid, the nozzle-moving mechanism 50 isoperated and the nozzle 20 is moved based on an operation signaltransmitted from the control unit (not illustrated). After beingejected, the solvent in the material liquid evaporates before reachingthe substrate layer, and thereby the ejected material liquid is spun soas to be drawn toward the collecting unit 40 while forming fibers F. Thefibers F are deposited onto the substrate layer provided on thecollecting unit 40, to thereby form a deposit of fibers F. This depositbecomes the nanofiber layer.

Next, based on an operation signal transmitted from the control unit(not illustrated), the nanofiber sheet 10 is cut by operating thecutting unit-moving mechanism 70 to thereby move the cutting unit 7while emitting a laser beam from the cutting unit 7. In this way, ananofiber sheet 10 having a desired planar-view shape is formed. Thecutting unit 7 is configured to cut only the nanofiber layer on thesubstrate layer, or cut only the substrate layer located outside theperipheral edge of the deposited nanofiber layer, or cut the entirenanofiber sheet 10 including both the substrate layer and the nanofiberlayer, depending on e.g., conditions for emitting the laser beam.

From the viewpoint of formability of the nanofiber sheet 10, it ispreferable that at least one of the nozzle 20, the cutting unit 7, orthe collecting unit 40 is moved at a constant speed. The preferablerange for the movement speed of each of these components may be the sameas the range described above regarding “the movement speed of either oneof the nozzle 20 or the collecting unit 40”.

Preferably, the entire electrospinning device 100A of the presentembodiment is covered by a cover, taking into consideration that thedevice may be installed at a store counter. It is preferable that atransparent section is provided in at least a portion of the cover. Fromthe viewpoint of attenuating inadvertently-escaping laser beams, it ispreferable that the transparent section is made from a material that caneasily absorb light with laser beam wavelengths, e.g., acrylic resin,polycarbonate resin, or glass.

In cases where the entire electrospinning device 100A is covered with acover, it is preferable to provide a dust collection/deodorizationmechanism for deodorizing the smell of burning at the time of cuttingthe nanofiber sheet 10 by irradiation with a laser beam, taking intoconsideration that the device may be installed at a store counter.

FIG. 17 illustrates a third embodiment of an electrospinning device. Asregards electrospinning devices according to the following third,fourth, and fifth embodiments, features that are different from theelectrospinning device 100A of the foregoing second embodiment will bedescribed below. Features that are not particularly explained are thesame as those in the electrospinning device according to the foregoingsecond embodiment, and the explanation on the electrospinning device isapplicable as appropriate.

The aforementioned electrospinning device 100A includes a nozzle-movingmechanism 50 and a cutting unit-moving mechanism 70 separate from thenozzle-moving mechanism 50. In the electrospinning device 100B of thesecond embodiment, the cutting unit 7 is mounted to the nozzle-movingmechanism 50.

In the electrospinning device 100B illustrated in FIG. 17, thecollecting unit-moving mechanism 80 is placed in a central portion ofthe base 90. The nozzle-moving mechanism 50 is arranged in a peripheraledge portion of the base 90. The nozzle-moving mechanism 50 of theelectrospinning device 100B includes: a slider 51 configured to retainthe nozzle 20; and an X-axis rail 53, a Y-axis rail 55 and a Z-axis rail52. The slider 51 is fitted in a guide groove 57 formed in the Z-axisrail 52. The slider 51 retains the nozzle 20, and also retains thecutting unit 7. With this nozzle-moving mechanism 50, the slider 51 canmove freely in the X-axis direction, the Y-axis direction, and theZ-axis direction. As a result, the nozzle 20 and the cutting unit 7 canmove freely in the X-axis direction, the Y-axis direction, and theZ-axis direction.

In the electrospinning device 100B of the present embodiment, the nozzle20 and the cutting unit 7 are supported by the slider 51 constitutingthe nozzle-moving mechanism 50. Stated differently, the nozzle-movingmechanism 50 and the cutting unit 7 are supported by a common support.As a result, the nozzle 20 and the cutting unit 7 can be moved freely intriaxial directions by the nozzle-moving mechanism 50. Since theelectrospinning device 100B includes both the manufacturing unit formanufacturing the nanofiber sheet 10 and the cutting unit for cuttingthe nanofiber sheet 10 into a predetermined contour shape within thesame nozzle-moving mechanism 50, the entire device can be made even morecompact.

As in the aforementioned electrospinning device 100A, in a method formanufacturing a nanofiber sheet 10 using the electrospinning device100B, a nanofiber sheet 10 is manufactured by forming a nanofiber layeron a substrate layer arranged on the collecting unit 40 by ejecting amaterial liquid from the nozzle 20 while moving the nozzle 20 byoperating the nozzle-moving mechanism 50 based on an operation signaltransmitted from the control unit (not illustrated). Next, based on anoperation signal transmitted from the control unit (not illustrated),the nanofiber sheet 10 is cut by operating the nozzle-moving mechanism50 to thereby move the cutting unit 7 while emitting a laser beam fromthe cutting unit 7. In this way, a nanofiber sheet 10 having a desiredshape is formed.

The aforementioned electrospinning device 100A illustrated in FIG. 16includes a collecting unit-moving mechanism 80 placed in a centralportion of the base 90, and a nozzle-moving mechanism 50 and a cuttingunit-moving mechanism 70 arranged at peripheral edge portions of thebase 90 in opposition to one another. Alternatively, the electrospinningdevice may include a nozzle-moving mechanism 50 and a collectingunit-moving mechanism 80 without including a cutting unit-movingmechanism 70, and instead, a cutting unit 7 may be fixed to a supportcolumn provided so as to stand in a peripheral edge portion of the base90. Also in such a device, the nozzle-moving mechanism 50 and thecutting unit 7 will be supported by the base 90 serving as a commonsupport, and thus, the entire device will be extremely compact.

Next, fourth and fifth embodiments of electrospinning devices will bedescribed. FIGS. 18 and 19 illustrate a cartridge unit 1 used inelectrospinning devices according to the fourth and fifth embodiments.As illustrated in FIG. 18, the cartridge unit 1 includes: a housingportion 2 capable of housing a material liquid; and a nozzle 20configured to eject the material liquid. The cartridge unit 1 alsoincludes a supplying portion 3 configured to supply the material liquidfrom the housing portion 2 to the nozzle 20.

The housing portion 2 is constituted by one of various containers suchas a synthetic resin-made pouch. For example, in cases where the housingportion 2 is constituted by a pouch, the housing portion can be formedby superposing two sheets of synthetic resin-made films having the sameshape and same size, and joining the respective peripheral edges thereofin a liquid-tight manner, as illustrated in FIGS. 18 and 19. The housingportion 2 has, in its peripheral edge portion, an opening 4 throughwhich a material liquid can be filled and fed out. The interior space ofthe housing portion 2 can be filled with the material liquid through theopening 4, and the material liquid filled in the housing portion 2 canbe fed to the outside through the opening.

The nozzle 20 includes an ejection hole (not illustrated) having aminute diameter. The nozzle 20 is made from a non-electroconductivematerial, such as a synthetic resin. An electroconductive needle-shapedelectrode (not illustrated) is arranged inside the ejection hole alongthe longitudinal direction of the ejection hole. The electrode is usedfor charging the material liquid ejected through the nozzle 20. Theelectrode is connected to a later-described power supply. As a result, apositive or negative voltage can be applied to the nozzle 20. An end ofthe ejection hole of the nozzle 20 is directly connected to thesupplying portion 3 of the cartridge unit 1. “Directly connected” meansthat the nozzle 20 and the supplying portion 3 are connected in a statewhere no supplying tube, which is a separate member from the nozzle andthe supplying portion, is interposed therebetween. The other end of theejection hole is opened toward the outside.

The supplying portion 3 functions to supply the material liquid housedwithin the housing portion 2 to the nozzle 20. To achieve this, thesupplying portion 3 includes a liquid-feeding mechanism (notillustrated) for feeding the material liquid. For the liquid-feedingmechanism, any known mechanism may be used without particularlimitation. For example, a gear pump may be used as the liquid-feedingmechanism. A gear pump can suitably be used in the present inventionbecause it is compact and can quantitatively feed the material liquidwith high precision. The supplying portion 3 also includes an engagementconnection portion 5 for connection with a drive source (describedfurther below) configured to drive the liquid-feeding mechanism. Theengagement connection portion 5 is configured to be engaged with anengaging/connecting portion (not illustrated) of the drive source, andthereby, a drive force generated by the drive source is transmitted tothe liquid-feeding mechanism.

As illustrated in FIG. 19, the supplying portion 3 includes a receivingportion 6 for receiving the material liquid. The receiving portion 6 hasa cylindrical base portion 6 a. The receiving portion 6 also has acylindrical liquid-receiving tube 6 b having a smaller diameter thanthat of the base portion 6 a and being contiguous to the upper end ofthe base portion 6 a. In the figure, the tip end of the liquid-receivingtube 6 b is opened upward. When the cartridge unit 1 is in use, thereceiving portion 6 is inserted in the opening 4 of the housing portion2, and thereby the housing portion 2 is detachably mounted to thesupplying portion 3. More specifically, in a state where the receivingportion 6 is inserted in the opening 4, the tip end of theliquid-receiving tube 6 b reaches the space inside the housing portion 2where the material liquid is housed, which allows the material liquid tobe supplied to the supplying portion 3. The base portion 6 a is fittedwith the opening 4 in a liquid-light manner, thereby maintaining thelinked state between the housing portion 2 and the supplying portion 3.In this state where the housing portion 2 is mounted to the supplyingportion 3, the housing portion 2 and the supplying portion 3 aredirectly connected. “Directly connected” means that the housing portion2 and the supplying portion 3 are connected in a state where nosupplying tube, which is a separate member from the housing portion andthe supplying portion, is interposed therebetween.

By configuring the cartridge unit 1 as described above, the presentembodiment becomes advantageous in that, when a different type ofnanofiber sheet is to be manufactured by changing the type of materialliquid, this can be achieved by the simple operation of removing thehousing portion 2 and exchanging it with another housing portion 2containing a different material liquid. Further, the nozzle 20, which isa relatively expensive member, can be reused, thus making the deviceeconomical. Moreover, the housing portion 2 and the supplying portion 3are directly connected, and also the supplying portion 3 and the nozzle20 are directly connected; this configuration is advantageous in that,when exchanging the cartridge unit 1 to use a different material liquid,the flow path for the material liquid inside the cartridge unit 1 can becleaned easily.

FIG. 20 illustrates an electrospinning device 100C according to a fourthembodiment. The electrospinning device 100C illustrated in FIG. 20includes the cartridge unit 1 illustrated in FIGS. 18 and 19. Theelectrospinning device 100C has a similar configuration to theelectrospinning device 100A according to the second embodiment, exceptthat it includes the cartridge unit 1 which is provided with the nozzle20, and that the nozzle-moving mechanism 50 is configured to move theentire cartridge unit 1.

The nozzle-moving mechanism 50 is configured so as to be able to movethe cartridge unit 1, which includes the nozzle 20, at least within arange in which the collecting unit 40 is movable. Except for thisconfiguration, the nozzle-moving mechanism 50 of the present embodimenthas a similar configuration to the nozzle-moving mechanism 50 of thesecond embodiment.

As described above, in the nozzle-moving mechanism 50, the cartridgeunit 1 is detachably mounted to the slider 51. Stated differently, theslider 51 is not only used as a means for raising and lowering thecartridge unit 1, but is also used as a mounting unit for mounting thecartridge unit 1. The slider 51, serving as the mounting unit for thecartridge unit 1, is provided with a drive source 8 configured to drivethe supplying portion 3 (see FIGS. 18 and 19) of the cartridge unit 1.The drive source 8 includes an engaging/connecting portion (notillustrated) configured to engage with the engagement connection portion5 (see FIGS. 18 and 19) of the supplying portion 3. In a state where thecartridge unit 1 is mounted to the slider 51 serving as the mountingunit, the engagement connection portion 5 of the supplying portion 3 isin engagement with the engaging/connecting portion (not illustrated) ofthe drive source 8, and thereby, the drive force generated by the drivesource 8 is transmitted to the supplying portion 3.

As described above, in the present embodiment, the cartridge unit 1 isdetachably mounted to the slider S1. This configuration is advantageousin that, when a different type of nanofiber sheet is to be manufacturedby changing the type of material liquid, the manufacture of a new typeof nanofiber sheet can be achieved by the simple operation of removingthe cartridge unit 1 from the slider 51 and exchanging it with anothercartridge unit 1 containing a different material liquid. This advantagebecomes particularly significant in cases where the housing portion 2 isnot detachable from the supplying portion 3 in the cartridge unit 1.

The cartridge unit 1 is detachably mounted to the slider 51, serving asthe mounting unit, in an electrically insulated state. In this way, itis possible to effectively suppress unintended discharge, even in caseswhere a high voltage is applied to the nozzle 20 provided to thecartridge unit 1.

The collecting unit-moving mechanism 80, the nozzle-moving mechanism 50,and the cutting unit-moving mechanism 70 are electrically connected to acontrol unit (not illustrated), and the collecting unit 40, thecartridge unit 1, and the cutting unit 7 can be moved based on dataabout movement paths inputted to the control unit and/or operationsignals inputted to the control unit by an operator via a controller.

FIG. 21 illustrates an electrospinning device 100D according to a fifthembodiment. The electrospinning device 100D illustrated in FIG. 21includes the cartridge unit 1 illustrated in FIGS. 18 and 19. In theelectrospinning device 100D, the cutting unit 7 is mounted to thenozzle-moving mechanism 50.

In the electrospinning device 100D illustrated in FIG. 21, thecollecting unit-moving mechanism 80 is placed in a central portion ofthe base 90. The nozzle-moving mechanism 50 is arranged in a peripheraledge portion of the base 90. The nozzle-moving mechanism 50 of theelectrospinning device 100D includes: a slider 51 to which the cartridgeunit 1, including the nozzle 20, is detachably mounted; rails 53 and 55;and a Z-axis rail 52. The slider 51 is fitted in a guide groove 57formed in the Z-axis rail 52. The slider 51 retains the cartridge unit 1and the cutting unit 7. With this nozzle-moving mechanism 50, the slider51 can move freely in the X-axis direction, the Y-axis direction, andthe Z-axis direction. As a result, the cartridge portion 1, includingthe nozzle 20, and the cutting unit 7 can move freely in the X-axisdirection, the Y-axis direction, and the Z-axis direction.

In the electrospinning device 100D of the present embodiment, thecartridge unit 1, including the nozzle 20, and the cutting unit 7 aresupported by the slider 51 constituting the nozzle-moving mechanism 50.Staled differently, the nozzle-moving mechanism 50 and the cutting unit7 are supported by a common support. As a result, the nozzle 20 and thecutting unit 7 can be moved freely in triaxial directions by thenozzle-moving mechanism 50. Since the electrospinning device 100Dincludes both the manufacturing unit for manufacturing the nanofibersheet 10 and the cutting unit for cutting the nanofiber sheet 10 into apredetermined contour shape within the same nozzle-moving mechanism 50,the entire device can be made even more compact.

Next, material liquids that may be used in nanofiber sheet manufacturingmethods using the aforementioned electrospinning devices will bedescribed.

For the material liquid, it is possible to use a solution or dispersionin which a fiber-formable polymer compound has been dissolved ordispersed in a solvent. For the fiber-formable polymer compound, it ispossible to use any of the aforementioned polymer compounds for thenanofibers.

In addition to the aforementioned polymer compounds, the material liquidmay include, for example, inorganic particles, organic particles, plantextracts, surfactants, oily agents, electrolytes for adjusting ionconcentration, and the like, as appropriate.

Examples of solvents for the material liquid may include water,methanol, ethanol, 1-propanol, 2-propanol, bexafluoroisopropanol,1-butanol, isobutyl alcohol, 2-butanol, 2-methyl-2-propanol,tetraethylene glycol, triethylene glycol, dibenzyl alcohol,1,3-dioxolane, 1,4-dioxane, methyl ethyl ketone, methyl isobutyl ketone,methyl-n-hexyl ketone, methyl-n-propyl ketone, diisopropyl ketone,diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid,methyl formate, ethyl formate, propyl formate, methyl benzoate, ethylbenzoate, propyl benzoate, methyl acetate, ethyl acetate, propylacetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate,methyl chloride, ethyl chloride, methylene chloride, chloroform,o-chlorotoluene, p-chlorotoluene, carbon tetrachloride,1,1-dichloroethane, 1,2-dichloroethane, trichloroethane,dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethylbromide, propyl bromide, acetic acid, benzene, toluene, hexane,cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene,acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and pyridine. Theaforementioned solvent may be used singly, or a plurality of solventsmay be used as a mixture.

The aforementioned nanofiber layer 11 is layered on a sheet-likearticle, which becomes the substrate layer 12, either directly or withan adhesive layer interposed therebetween. The nanofiber layer 11 andthe substrate layer 12 may be integrated, for example, by fixing, suchas adhesion using an adhesive, compression-bonding, joining byultrasonic sealing, fusion-bonding by a laser, or thermal fusion-bondingby heat sealing. In cases where the nanofiber sheet includes an adhesivelayer, at least one, or both, of the nanofiber layer 11 and thesubstrate layer 12, as well as the substrate layer 12 and the adhesivelayer, may be integrated by the aforementioned fixing.

The aforementioned nanofiber sheet may be manufactured by forming agradation region G in which the deposition amount of fibers F graduallyincreases by changing the spinning direction of the fibers F, withoutmoving the nozzle 20 or the counter electrode 30. For example, thenozzle 20 may be provided with an airflow jetting unit for jetting anairflow, and the fibers F may be deposited while blowing the airflowonto the fibers F such that the fibers F are deposited at desiredpositions.

The foregoing description relates to producing nanofibers byelectrospinning and manufacturing nanofiber sheets by depositing thenanofibers on one surface of a substrate layer. The present invention,however, is applicable to fibers other than nanofibers, such as fibersthicker than nanofibers. Further, the present invention is alsoapplicable to particles produced by electrostatic spraying and collectedby a collecting unit.

More specifically, the present invention encompasses laminate sheets,including: a substrate layer; and an ultrathin sheet located on onesurface of the substrate layer. Preferably, the ultrathin sheet is madefrom a deposit of fibers or particles. Stated differently, the ultrathinsheet is preferably a fiber sheet or a film-like sheet. The fibers orparticles constituting the ultrathin sheet can be produced from amaterial liquid for the fibers or particles by ejecting the materialliquid from a nozzle. In cases of producing fibers from a materialliquid, the method therefor is not particularly limited, and forexample, melt spinning may be employed.

The thickness of fibers produced from the material liquid is, forexample, preferably 10 nm or greater, more preferably 0.1 μm or greater,even more preferably 0.3 μm or greater. The thickness of fibers producedfrom the material liquid is preferably 30 μm or less, more preferably 3μm or less, even more preferably 1 μm or less. Particularly, thethickness of fibers produced from the material liquid is preferably from10 nm to 30 μm, more preferably from 0.1 to 3 μm, even more preferablyfrom 0.3 to 1 μm.

The materials of the fibers contained in the material liquid may be thesame as the materials constituting the aforementioned nanofiber layer11.

The particle size may preferably be, for example, 0.01 μm or greater,more preferably 0.1 μm or greater, even more preferably 1 μm or greater.The particle size may preferably be 200 μm or less, more preferably 100μm or less, even more preferably 10 μm or less. Particularly, theparticle size may preferably be from 0.01 to 200 μm, more preferablyfrom 0.1 to 100 μm, even more preferably from 1 to 10 μm. The size of

of the human body, it is preferable to form the ultrathin sheet into acontour shape corresponding to the usage, or a contour shapecorresponding to the surface portion. For example, in cases where theultrathin sheet is to be applied to a section below the eye, it ispreferable to use an ultrathin sheet having an oval-shaped contourprovided with a curved part in a portion thereof, as illustrated in FIG.1, from the viewpoint of improving fittability. From the same viewpoint,in cases where the ultrathin sheet is to be applied to the cheek, it ispreferable to use an ultrathin sheet having a triangular contour withrounded corners and/or with arc-shaped sides that bulge outward. Fromthe same viewpoint, in cases where the ultrathin sheet is to be appliedto the forehead, it is preferable to use an ultrathin sheet having asubstantially elliptic contour. Further, for example, in cases of usingthe ultrathin sheet for uses to correct/conceal spots or moles on thesurface of the human body or unevenly-colored spots on the skin, theshape of the ultrathin sheet may be circular, elliptic, rectangular withrounded corners, or a combination thereof.

Regardless of what kind of contour shape the ultrathin sheet has, it ispreferable that the contour outline of the ultrathin sheet a shapewherein more than half the length, of the entire length of the contouroutline, is constituted by a curve, from the viewpoint of improvingfittability between the ultrathin sheet and the section to which theultrathin sheet is to be applied. From the viewpoint of furtherenhancing this advantage, it is preferable that the contour outline ofthe ultrathin sheet is a shape wherein curvilinear sections occupypreferably at least 60%, more preferably at least 70%, even morepreferably at least 80%, of the entire length of the contour outline,and it is further preferable that the entire contour outline of theultrathin sheet is constituted by curves. The contour outline can bedetermined from the planar contour curve as described above in “Methodfor Measuring Thickness of Peripheral Edge.”

The ultrathin sheet includes a tapered peripheral edge region having athickness that gradually increases inward from the peripheral edge ofthe ultrathin sheet. “Tapered” refers to a cross-sectional shape of theperipheral edge region when the ultrathin sheet is viewed along itsthickness direction. The “tapered peripheral edge region” is synonymousto the aforementioned “gradation region G.”

Preferably, the tapered peripheral edge region is formed in a regionthat is within a width of 5 mm or less extending inward from theperipheral edge of the ultrathin sheet. The “width of the taperedperipheral edge region” is synonymous to the width W1 of the gradationregion G in the aforementioned nanofiber sheet. The width of the taperedperipheral edge region may be the same at any position in the peripheraledge region, or may vary depending on the position. In cases where thewidth of the tapered peripheral edge region varies depending on theposition, it is preferable that the minimum width is within 5 mm.

The ultrathin sheet includes an inner region surrounded by the taperedperipheral edge region in a position more inward than the peripheraledge region. The inner region is a region having a substantiallyconstant thickness, in contrast to the peripheral edge region. The“thickness of the ultrathin sheet” refers to the thickness at the innerregion. The thickness of the inner region—i.e., the thickness of theultrathin sheet—is preferably 5.1 μm or greater, more preferably 10 μmor greater. The thickness of the ultrathin sheet is preferably 500 μm orless, more preferably 400 μm or less. Particularly, the thickness of theultrathin sheet is preferably from 5.1 to 500 μm, more preferably from10 to 400 μm.

As described above, the inner region is a region having a substantiallyconstant thickness. Thus, the thickness of the inner region may slightlyvary depending on the position. For example, it is permissible that thethickness varies within a range of around ±25% with respect to theaverage thickness.

In a cross section along the thickness direction of the ultrathin sheet,the width of the inner region is preferably 100 mm or less, morepreferably 50 mm or less, even more preferably 30 mm or less. Theminimum value of the width of the inner region is 0 mm; i.e., the innerregion does not have to exist. The “width of the inner region” issynonymous to the “width W2 of the inner region M” in the aforementionednanofiber sheet (see FIG. 2).

The thickness of the inner region and the thickness of the peripheraledge region of the ultrathin sheet can be measured according to theaforementioned “Method for Measuring Three-dimensional Shape ofNanofiber Layer”. This measurement method is also applicable to themeasurement of the thickness of the gradation region G and the thicknessof the inner region M of the aforementioned nanofiber sheet.

Preferably, the substrate layer of the laminate sheet includes a region(also referred to as “extension region”) that extends outward from theperipheral edge of the ultrathin sheet. This is the same as theconfiguration that, in the aforementioned nanofiber sheet 10, thesubstrate layer 12 includes a region that extends outward from theperipheral edge of the nanofiber layer 11, as illustrated in FIGS. 1 to3. Providing the substrate layer of the laminate sheet with an extensionregion allows the ultrathin sheet to be peeled easily from the substratelayer.

The substrate layer of the laminate sheet may extend outward from theentire region of the ultrathin sheet's peripheral edge, or may extendoutward from a portion of the peripheral edge. In either case, thedegree of extension of the extension region may vary depending on theposition, or may be the same. In cases where the substrate layer extendsoutward from the entire region of the ultrathin sheet's peripheral edgeand the degree of extension of the extension region is the sameregardless of position, then the contour shape of the substrate layerwill have a substantially similar shape to the contour shape of theultrathin sheet. Making the contour shapes of the substrate layer andthe ultrathin sheet similar to one another is advantageous as follows.The ultrathin sheet is extremely thin, and may thus be difficult toobserve with the eyes. In contrast, the substrate layer is easilyobservable with the eyes; so, forming the contour shape of the ultrathinsheet substantially similar to the contour shape of the substrate layercan facilitate recognition of the presence of the ultrathin sheet andalso facilitate peeling from the substrate sheet through visualrecognition of the contour shape of the substrate layer.

The present invention is applicable to an ultrathin sheet manufacturingmethod for manufacturing an ultrathin sheet having a thickness from 5.1to 500 μm by ejecting a material liquid from a nozzle and depositing,onto a collecting unit, fibers or particles produced from the materialliquid.

The present invention is also applicable to an ultrathin sheetmanufacturing method for manufacturing an ultrathin sheet having athickness from 5.1 to 500 μm by ejecting a material liquid from a nozzleand depositing, onto a substrate on a collecting unit, particlesproduced from the material liquid.

The description given above regarding fibers or particles produced froma material liquid is applicable as appropriate to these ultrathin sheetmanufacturing methods. Also, the description given above about theultrathin sheet is applicable as appropriate to ultrathin sheetsobtained by these manufacturing methods.

The ultrathin sheet manufacturing method includes an intended-shapeforming step. Like the aforementioned nanofiber sheet manufacturingmethod, in the intended-shape forming step, based on informationrelating to an intended contour shape of the ultrathin sheet, thematerial liquid is ejected within a range of the contour shape of theultrathin sheet while moving at least either the nozzle or thecollecting unit. The positional relationship between the nozzle and thecollecting unit may be, for example, the same as that in the embodimentillustrated in FIG. 9. The drive mechanism for the nozzle and thecollecting unit may also be the same as that in the embodimentillustrated in FIG. 9.

In the intended-shape forming step, the material liquid is ejected so asto form a tapered peripheral edge region having a thickness thatgradually increases inward from a peripheral edge of the contour shapeof the intended ultrathin sheet. Herein, “tapered” refers to thecross-sectional shape of the peripheral edge region when the ultrathinsheet is viewed along its thickness direction. The “tapered peripheraledge region” is synonymous to the aforementioned “gradation region G”,and thus the description given above is applicable as appropriate.

The present invention has been described above according to preferredembodiments thereof, but the present invention is not limited to theforegoing embodiments and can be modified as appropriate.

For example, in the electrospinning device 100 according to theforegoing embodiment, the collecting unit 40 serves also as the counterelectrode 30; however, the collecting unit 40 and the counter electrode30 may be separate members. In this case, the collecting unit 40 and thecounter electrode 30 may be arranged adjacent to one another.

In the foregoing embodiments, the nanofiber sheet 10 includes asubstrate layer 12; however, the substrate layer 12 does not have to beprovided.

In the foregoing embodiments, the factors relating to the depositiondistribution of nanofibers employed in the path calculation step are themovement speed of the nozzle 20, the ejection speed of the materialliquid, and the distance between the nozzle 20 and the collecting unit40; instead, other factors may be employed, or the aforementionedfactors may be employed in combination with other factors.

In the foregoing embodiments of the electrospinning device, the slider51, serving as the mounting unit for the nozzle 20 or the cartridge unit1, is mounted to a biaxial movement mechanism; instead, it may bemounted to an at-least uniaxial movement mechanism. Similarly, thecollecting unit 40 and the slider 71 may be mounted to an at-leastuniaxial movement mechanism.

In the foregoing embodiments, the base 90 in each device is constitutedby a single member, instead, the base may be made of two or more membersconnected by an optional connection means or fastening means, and may beused as a substantially single member.

In the foregoing embodiments, each device includes a nozzle-movingmechanism 50; instead, the nozzle 20, or the cartridge unit 1 includingthe same, may be immovably fixed to another support within the device,without using a nozzle-moving mechanism 50. A device according to suchan embodiment will require at least a collecting unit-moving mechanism80. An example of a device in which the nozzle 20 is immovably fixed mayinclude a base 90 located in opposition to the nozzle 20, a collectingunit-moving mechanism 80 placed in a central portion of the base 90, anda cutting unit-moving mechanism 70 located in a peripheral edge portionof the base 90, wherein the collecting unit-moving mechanism 80 and thecutting unit-moving mechanism 70 are supported by the base 90 serving asa common support. This device will also be extremely compact as a whole.Another example of a device in which the nozzle 20 is immovably fixedmay include a base 90 located in opposition to the nozzle 20, acollecting unit-moving mechanism 80 placed in a central portion of thebase 90, and a cutting unit 7 immovably fixed to a support columnprovided so as to stand in a peripheral edge portion of the base 90,wherein the collecting unit-moving mechanism 80 and the cutting unit 7are supported by the base 90 serving as a common support.

The electrospinning device 100A according to the embodiment illustratedin FIG. 16 and the electrospinning device 100C according to theembodiment illustrated in FIG. 20 include a collecting unit-movingmechanism 80 placed in a central portion of the base 90, and anozzle-moving mechanism 50 and a cutting unit-moving mechanism 70arranged at peripheral edge portions of the base 90 in opposition to oneanother. Instead, the electrospinning device may include a nozzle-movingmechanism 50 but may lack a collecting unit-moving mechanism 80, and acollecting unit 40 may be fixed in a central portion of the base 90.Alternatively, the electrospinning device may be configured including acollecting unit-moving mechanism 80 but lacking a cutting unit-movingmechanism 70, and a cutting unit 7 may be fixed to a support columnprovided so as to stand in a peripheral edge portion of the base 90.Even in these devices, the nozzle-moving mechanism 50 and the cuttingunit 7 are supported by the base 90, which serves as a common support,and thus, the entire device will be extremely compact.

The electrospinning device 100B according to the embodiment illustratedin FIG. 17 and the electrospinning device 100D according to theembodiment illustrated in FIG. 21 include a collecting unit-movingmechanism 80 placed in a central portion of the base 90, and anozzle-moving mechanism 50 arranged in a peripheral edge portion of thebase 90, wherein a nozzle 20, or a cartridge unit 1 including the same,and a cutting unit 7 are mounted to the nozzle-moving mechanism 50.Instead, the electrospinning device may include a nozzle-movingmechanism 50 but may lack a collecting unit-moving mechanism 80, and acollecting unit 40 may be fixed in a central portion of the base 90.Even in this device, the nozzle 20 and the cutting unit 7 are supportedby the nozzle-moving mechanism 50, which serves as a common support, andthus, the entire device will be extremely compact. Further, theelectrospinning device may be configured including a collectingunit-moving mechanism 80 but lacking a cutting unit-moving mechanism 70,and a nozzle 20 and a cutting unit 7 may be fixed to a support columnprovided so as to stand in a peripheral edge portion of the base 90.Even in this device, the nozzle-moving mechanism 50 and the cutting unit7 are supported by the base 90, which serves as a common support, andthus, the entire device will be extremely compact.

The electrospinning devices according to the foregoing embodimentsinclude a voltage application unit 32 serving as a power supplyconfigured to apply a voltage to the nozzle 20. Instead, theelectrospinning device may include a material jetting unit provided witha nozzle, a counter electrode located in opposition to the nozzle andhaving a concave-curved surface configured to create an electric fieldbetween it and the nozzle, and a voltage-generating unit serving as apower supply configured to apply a voltage between the nozzle and thecounter electrode, as disclosed in JP 2017-31517A. According to thedevice disclosed in this publication, nanofibers can be deposited on asubstrate layer arranged on a collecting unit while blowing an airflowtoward the collecting unit.

In relation to the foregoing embodiments, the present invention furtherdiscloses the following nanofiber sheets, methods for using the same,methods for manufacturing the same, and nanofiber sheet manufacturingdevices.

{1}.

A nanofiber sheet comprising:

-   -   a substrate layer; and    -   a nanofiber layer located on one surface side of the substrate        layer and containing nanofibers of a polymer compound, wherein:    -   a peripheral edge of the nanofiber layer has a thickness of from        0.1 to 10 μm; and    -   the nanofiber layer includes at least 3 mm of a gradation region        having a thickness that gradually increases inward from the        peripheral edge.

{2}

A laminate sheet comprising,

-   -   a substrate layer; and    -   an ultrathin sheet located on one surface of the substrate layer        and having a thickness of from 5.1 to 500 μm, wherein:    -   the ultrathin sheet has a contour shape corresponding to an        application-target section to which the ultrathin sheet is to be        applied;    -   the ultrathin sheet includes a tapered peripheral edge region        having a thickness that gradually increases inward from a        peripheral edge of the ultrathin sheet; and    -   the substrate layer includes a region that extends outward from        the peripheral edge of the ultrathin sheet.

{3}

The nanofiber sheet as set forth in clause {1} or the laminate sheet asset forth in clause {2}, wherein the thickness of the peripheral edge is0.3 μm or greater, preferably 0.5 μm or greater, and 9 μm or less,preferably 8 μm or less, and from 0.3 to 9 μm, preferably from 0.5 to 8μm.

{4}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {3}, wherein thickness D3 of a maximum thickness portion,which is the inner end of the gradation region or the tapered peripheraledge region, is 5.1 μm or greater, preferably 10 μm or greater, and 500μm or less, preferably 400 μm or less, and from 5.1 to 500 μm,preferably from 10 to 400 μm.

{5}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {4}, wherein an inclination angle of the gradation regionor the tapered peripheral edge region is 0.001° or greater, preferably0.002° or greater, and 10° or less, preferably 8° or less, and from0.001° to 10°, preferably from 0.002° to 8°.

{6}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {5}, wherein a difference in thickness between theperipheral edge and the inner end of the gradation region or the taperedperipheral edge region is 5 μm or greater.

{7}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {6}, wherein a difference in thickness between theperipheral edge and a maximum thickness portion, which is the inner endof the gradation region or the tapered peripheral edge region, is 5 μmor greater, preferably 10 μm or greater, and 500 μm or less, preferably400 μm or less, and from 5 to 500 μm, preferably from 10 to 400 μm.

{8}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {7}, wherein a ratio (D3/D1) of thickness D3 of themaximum thickness portion, which is the inner end of the gradationregion or the tapered peripheral edge region, to thickness D1 of theperipheral edge is 50 or greater, preferably 100 or greater, and 5000 orless, preferably 4000 or less, and from 50 to 5000, preferably from 100to 4000.

{9}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {8}, wherein a planar-view shape of the nanofiber layeror the ultrathin sheet is

-   -   a shape including, in its contour, a plurality of curvilinear        sections having different curvatures,    -   a shape including, in its contour, a plurality of rectilinear        sections, or    -   a shape including, in its contour, both the curvilinear sections        and the rectilinear sections.

{10}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {9}, wherein:

-   -   the nanofiber layer or the ultrathin sheet is located adjacent        to the substrate layer; and    -   the substrate layer has air permeability.

{11}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {10}, wherein the substrate layer is a nonwoven fabric.

{12}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {11}, wherein the substrate layer is a sponge.

{13}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {12}, wherein:

-   -   the nanofiber layer or the ultrathin sheet is located adjacent        to the substrate layer; and    -   the substrate layer has, on a surface facing the nanofiber layer        or the ultrathin sheet, a plurality of depressions or        projections each having a width greater than a fiber diameter of        the nanofiber.

{14}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {13}, wherein the nanofiber layer or the ultrathin sheetis water-insoluble.

{15}

The nanofiber sheet or the laminate sheet as set forth in clause {14},wherein:

-   -   the content of a water-insoluble polymer compound contained in        the nanofiber layer or the ultrathin sheet is more than 50 mass        %, preferably 80 mass % or greater; and    -   the content of a water-soluble polymer compound contained in the        nanofiber layer is preferably less than 50 mass %, more        preferably 20 mass % or less.

{16}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {15}, wherein:

-   -   the nanofiber layer or the ultrathin sheet contains another        component in addition to the nanofibers;    -   the content of the nanofibers in the nanofiber layer is from 40        to 95 mass %, preferably from 70 to 90 mass %; and    -   the content of the other component in the nanofiber layer or the        ultrathin sheet is from 5 to 60 mass %, preferably from 10 to 30        mass %.

{17}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {16}, wherein:

-   -   the nanofiber layer or the ultrathin sheet includes an inner        region surrounded by the gradation region or the tapered        peripheral edge region;    -   the inner region includes a depression; and    -   the thickness at the depression of the inner region, with        respect to the thickness at the maximum thickness portion, is        50% or greater, preferably 60% or greater, and 100% or less,        preferably 90% or less, and from 50 to 100%, preferably from 60        to 90%.

{18}

The nanofiber sheet or the laminate sheet as set forth in clause {17},wherein the thickness at the depression of the inner region is 5.1 μm orgreater, preferably 10 μm or greater, and 500 μm or less, preferably 400μm or less, and from 5.1 to 500 μm, preferably from 10 to 400 μm.

{19}

The nanofiber sheet or the laminate sheet as set forth in clause {17} or{18}, wherein:

-   -   the inner region includes, as the depressions,    -   a shallow depression forming a section having a greater        thickness than the maximum thickness portion, which is the inner        end of the gradation region or the ultrathin sheet, and    -   a deep depression forming a section having a smaller thickness        than the maximum thickness portion; and    -   the thickness at the shallow depression of the inner region is        5.1 μm or greater, preferably 10 μm or greater, and 500 μm or        less, preferably 400 μm or less, and from 5.1 to 500 μm,        preferably from 10 to 400 μm.

{20}

The nanofiber sheet or the laminate sheet as set forth in clause {19},wherein the thickness at the deep depression is 5.1 μm or greater,preferably 10 μm or greater, and 500 μm or less, more preferably 400 μmor less, and from 5.1 to 500 μm, more preferably from 10 to 400 μm.

{21}

The nanofiber sheet or the laminate sheet as set forth in any one ofclauses {1} to {20}, further comprising an adhesive layer adherable to asurface of an object, wherein

-   -   the adhesive layer is located between the substrate layer and        the nanofiber layer, or on a surface of the nanofiber layer on        an opposite side from the substrate layer.

{22}

The laminate sheet as set forth in any one of clauses {2} to {21},wherein the ultrathin sheet is formed by a nanofiber layer containingnanofibers of a polymer compound.

{23}

The laminate sheet as set forth in any one of clauses {2} to {22},wherein the thickness of the peripheral edge of the ultrathin sheet isfrom 0.1 to 10 μm.

{24}

The laminate sheet as set forth in any one of clauses {2} to {23},wherein the tapered peripheral edge region is formed in a region that iswithin a width of 5 mm or less extending inward from the peripheral edgeof the ultrathin sheet.

{25}

The laminate sheet as set forth in any one of clauses {2} to {24},wherein a contour outline of the ultrathin sheet is a shape wherein morethan half the length, of an entire length of the contour outline, isconstituted by a curve.

{26}

A method for using the nanofiber sheet or the laminate sheet as setforth in any one of clauses {1} to {25}, comprising

-   -   placing the nanofiber layer or the ultrathin sheet in contact        with a surface of an object, and using the nanofiber layer or        the ultrathin sheet in a moistened state.

{27}

The method for using the nanofiber sheet or the laminate sheet as setforth in clause {26}, comprising

-   -   making the nanofiber layer or the ultrathin sheet adhere to the        object's surface in a state where the object's surface is        moistened.

{28}

The method for using the nanofiber sheet or the laminate sheet as setforth in clause {26}, comprising

-   -   moistening the nanofiber layer or the ultrathin sheet in a state        where the nanofiber layer or the ultrathin sheet is adhering to        the object's surface.

{29}

The method for using the nanofiber sheet or the laminate sheet as setforth in clause {26}, comprising

-   -   making the nanofiber layer or the ultrathin sheet adhere to the        object's surface in a state where the nanofiber layer or the        ultrathin sheet is moistened.

{30}

A method for manufacturing a nanofiber sheet or a laminate sheet,comprising

-   -   ejecting a material liquid from a nozzle while applying a high        voltage between the nozzle and a counter electrode, and        depositing, onto a collecting unit, nanofibers produced from the        material liquid by electrospinning, wherein    -   a predetermined nanofiber sheet or laminate sheet including a        gradation region or tapered peripheral edge region having a        thickness that gradually increases inward from a peripheral edge        is manufactured by depositing the nanofibers onto the collecting        unit by moving at least either the nozzle or the collecting        unit.

{31}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {30}, comprising.

-   -   a path calculation step of determining a movement path for at        least either the nozzle or the collecting unit along which the        predetermined nanofiber sheet or laminate sheet can be formed,        the determining being based on a correlation between a factor        relating to deposition distribution of the nanofibers and a        deposition thickness of the nanofibers; and    -   a deposition step of depositing the nanofibers, while moving at        least either the nozzle or the collecting unit, in accordance        with the movement path determined in the path calculation step.

{32}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {31}, wherein the factor relating to depositiondistribution of the nanofibers is one factor, or a combination of two ormore factors, selected from the group consisting of a movement speed ofthe nozzle or the collecting unit, an ejection speed of the materialliquid, a potential difference between the nozzle and the counterelectrode, a distance between the nozzle and the collecting unit, aninner diameter of the nozzle, and a material of the nozzle.

{33}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {31} or {32}, wherein.

-   -   in a planar view, the predetermined nanofiber sheet or laminate        sheet includes an inner region surrounded by the gradation        region; and    -   in the path calculation step, the movement path is calculated        such that a minimum thickness of the inner region is equal to or        greater than a predetermined setting value.

{34}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {31} to {33}, wherein the depositionstep of depositing the nanofibers on the collecting unit while moving atleast either the nozzle or the collecting unit comprises:

-   -   a first step of moving either one of the nozzle or the        collecting unit along a first movement path such that a        deposited portion of the nanofibers forms a continuous first        deposition region; and    -   at least one second step of moving either one of the nozzle or        the collecting unit along a second movement path such that the        deposited portion of the nanofibers forms a second continuous        deposition region having a portion, in a width direction, that        continuously overlaps a portion, in the width direction, of the        first continuous deposition region or of a previously-formed        continuous deposition region.

{35}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {34}, wherein,

-   -   when a position that bisects the widthwise length of the        continuous deposition region is defined as a midpoint of said        continuous region, and a region where said continuous deposition        region and another continuous deposition region overlap one        another is defined as an overlap region,    -   the overlap region is located between, in the width direction,        -   the midpoint of said continuous deposition region and        -   an outer edge of said continuous deposition region located            on the side of the other continuous deposition region.

{36}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {35}, wherein, in the width direction, the midpointof said continuous deposition region and a midpoint of said othercontinuous deposition region are both located within the range of theoverlap region.

{37}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {34} to {36}, wherein,

-   -   when a previously-determined movement path is defined as a        determined path and a region surrounded by the first movement        path or a region surrounded by the determined path is defined as        a determined-path inner region,    -   the path calculation step calculates, within the determined-path        inner region,        -   a circulating similar path, which is substantially similar            to the planar-view shape of the deposit of nanofibers, or        -   a non-circulating path.

{38}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {37}, wherein the path calculation step calculatessaid similar path or said non-circulating path depending on the areaand/or shape of a range in which the movement path is to be set.

{39}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {37} or {38}, wherein, in the path calculation step,assessment is made as to whether or not said similar path can bearranged in a manner such that mutually corresponding sections in saiddetermined path and said similar path are adjoined adjacent to oneanother.

{40}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {30} to {39}, wherein the nozzle and/orthe collecting unit are/is moved at a constant speed.

{41}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {30} to {40}, wherein the movement pathalong which either one of the nozzle or the collecting unit moves is

-   -   a combination of a path group that includes, in a nested manner,        a plurality of paths substantially similar to one another, and a        crossover line that connects the plurality of paths, or    -   a linear shape that can be rendered in one stroke.

{42}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {30} to {41}, wherein a planar-viewshape of the nanofiber sheet or the laminate sheet is

-   -   a shape including, in its contour, a plurality of curvilinear        sections having different curvatures,    -   a shape including, in its contour, a plurality of rectilinear        sections, or    -   a shape including, in its contour, both the curvilinear sections        and the rectilinear sections.

{43}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {30} to {42}, comprising:

-   -   arranging a substrate layer on the collecting unit; and    -   depositing the nanofibers on the substrate layer.

{44}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {43}, comprising

-   -   a cutting step of        -   cutting the nanofiber sheet, the substrate layer, or both            the nanofiber sheet and the substrate layer, or        -   cutting the laminate sheet, the substrate layer, or both the            laminate sheet and the substrate layer.

{45}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {34} to {39}, wherein:

-   -   in a planar view, the predetermined nanofiber sheet or laminate        sheet includes an inner region surrounded by the gradation        region; and    -   when a region in which the continuous deposition region and        another continuous deposition region overlap one another is        defined as an overlap region, the minimum thickness of the        overlap region in the width direction with respect to the        minimum thickness of the inner region is 100% or greater,        preferably 125% or greater, and 250% or less, preferably 200% or        less, and from 100 to 250%, preferably from 125 to 200%.

{46}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {45}, wherein the minimum thickness of the overlapregion is 0.2 μm or greater, preferably 1 μm or greater, and 100 μm orless, preferably 10 μm or less, and from 0.2 to 100 μm, preferably from1 to 10 μm.

{47}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in clause {45} or {46}, wherein the overlap region's widthwith respect to the separation distance, in the width direction, betweenthe midpoint of one deposition region and the midpoint of anotherdeposition region is 1% or greater, preferably 5% or greater, and 90% orless, preferably 80% or less, and from 1 to 90%, preferably from 5 to80%.

{48}

The method for manufacturing a nanofiber sheet or a laminate sheet asset forth in any one of clauses {45} to {47}, wherein the overlapregion's width in the width direction is 1 mm or greater, preferably 4mm or greater, and 80 mm or less, preferably 60 mm or less, and from 1to 80 mm, preferably from 4 to 60 mm.

{49}

A device for manufacturing a nanofiber sheet or a laminate sheet,comprising:

-   -   a nozzle configured to eject a material liquid;    -   a counter electrode located in opposition to the nozzle and        configured to create an electric field between the nozzle and        the counter electrode;    -   a collecting unit configured to collect nanofibers produced by        electrically stretching the material liquid; and    -   a mechanism configured to move at least either the nozzle or the        collecting unit, wherein:    -   the manufacturing device is configured to be capable of        depositing the nanofibers onto the collecting unit while moving        at least either the nozzle or the collecting unit based on data        of a movement path inputted to a control unit; and    -   data on the movement path determined in the path calculation        step of the method for manufacturing a nanofiber sheet or        laminate sheet as set forth in clause {31} is inputted or is        inputtable to the control unit.

{50}

A device for manufacturing a nanofiber sheet or a laminate sheet,comprising:

-   -   a nozzle configured to eject a material liquid;    -   a power supply configured to apply a voltage to the nozzle, or    -   a counter electrode located in opposition to the nozzle and        configured to create an electric field between the nozzle and        the counter electrode, and a power supply configured to apply a        voltage between the nozzle and the counter electrode;    -   a collecting unit for depositing nanofibers produced from the        material liquid;    -   a nozzle-moving mechanism configured to move the nozzle relative        to the collecting unit; and    -   a cutting unit configured to cut the laminate sheet or the        nanofiber sheet, including a layer of the nanofibers deposited        on the collecting unit, into a predetermined shape, wherein    -   the nozzle-moving mechanism and the cutting unit are supported        by a common support.

{51}

The manufacturing device as set forth in clause {50}, wherein thecutting unit is provided to the nozzle-moving mechanism, and thereby,the nozzle-moving mechanism and the cutting unit are supported by thecommon support.

{52}

The manufacturing device as set forth in clause {50}, further comprisinga cutting unit-moving mechanism configured to move the cutting unitrelative to the collecting unit, wherein the cutting unit-movingmechanism is supported by the support and thereby the cutting unit andthe nozzle-moving mechanism are supported by the common support.

{53}

The manufacturing device as set forth in any one of clauses {50} to{52}, further comprising a collecting unit-moving mechanism configuredto move the collecting unit within its collecting plane, the collectingunit-moving mechanism being supported by the support.

{54}

A device for manufacturing a nanofiber sheet or a laminate sheet,comprising:

-   -   a nozzle configured to eject a material liquid;    -   a power supply configured to apply a voltage to the nozzle, or    -   a counter electrode located in opposition to the nozzle and        configured to create an electric field between the nozzle and        the counter electrode, and a power supply configured to apply a        voltage between the nozzle and the counter electrode;    -   a collecting unit for depositing nanofibers produced from the        material liquid;    -   a collecting unit-moving mechanism configured to move the        collecting unit relative to the nozzle; and    -   a cutting unit configured to cut the laminate sheet or the        nanofiber sheet, including a layer of the nanofibers deposited        on the collecting unit, into a predetermined shape, wherein    -   the collecting unit-moving mechanism and the cutting unit are        supported by a common support.

{55}

The manufacturing device as set forth in clause {54}, further comprisinga cutting unit-moving mechanism configured to move the cutting unitrelative to the collecting unit, wherein the cutting unit-movingmechanism is supported by the support and thereby the cutting unit andthe collecting unit-moving mechanism are supported by the commonsupport.

{56}

The manufacturing device as set forth in any one of clauses {50} to{55}, wherein the cutting unit is a laser processing machine.

{57}

The manufacturing device as set forth in any one of clauses {50} to{56}, wherein the collecting unit is air-permeable.

{58}

The manufacturing device as set forth in any one of clauses {50} to{57}, wherein: the entire manufacturing device is covered by a coverhaving a transparent section in at least a portion thereof; and

-   -   the transparent section is constituted by acrylic resin,        polycarbonate resin, or glass.

{59}

The manufacturing device as set forth in any one of clauses {50} to{58}, further comprising a dust collection/deodorization mechanism.

{60}

The manufacturing device as set forth in any one of clauses {50} to{59}, wherein:

-   -   the nanofiber sheet or laminate sheet includes a layer of the        nanofibers, and a substrate layer supporting the layer; and    -   the cutting unit is configured to cut only the layer of        nanofibers, or cut only the substrate layer, or cut the entire        nanofiber sheet or laminate sheet.

{61}

A device for manufacturing a nanofiber sheet or a laminate sheet,comprising:

-   -   a cartridge unit that includes a housing portion capable of        housing a material liquid, a nozzle configured to eject the        material liquid, and a supplying portion configured to supply        the material liquid from the housing portion to the nozzle;    -   a power supply configured to apply a voltage to the nozzle, or    -   a counter electrode located in opposition to the nozzle and        configured to create an electric field between the nozzle and        the counter electrode, and a power supply configured to apply a        voltage between the nozzle and the counter electrode;    -   a mounting unit for the cartridge unit; and    -   a collecting unit configured to collect nanofibers produced by        electrically stretching the material liquid, wherein:    -   the cartridge unit is detachably mounted to the mounting unit;        and    -   the mounting unit is provided with a drive source configured to        drive the supplying portion of the cartridge unit in a state        where the cartridge unit is mounted to the mounting unit.

{62}

A device for manufacturing a nanofiber sheet or a laminate sheet,comprising:

-   -   a cartridge unit that includes a housing portion capable of        housing a material liquid, a nozzle configured to eject the        material liquid, and a supplying portion configured to supply        the material liquid from the housing portion to the nozzle;    -   a power supply configured to apply a voltage to the nozzle, or    -   a counter electrode located in opposition to the nozzle and        configured to create an electric field between the nozzle and        the counter electrode, and a power supply configured to apply a        voltage between the nozzle and the counter electrode;    -   a mounting unit for the cartridge unit; and    -   a collecting unit configured to collect nanofibers produced by        electrically stretching the material liquid, wherein:    -   the mounting unit is provided with a drive source configured to        drive the supplying portion of the cartridge unit in a state        where the cartridge unit is mounted to the mounting unit; and    -   in the cartridge unit, the housing portion is detachably mounted        to the supplying portion.

{63}

The manufacturing device as set forth in clause {61} or {62}, wherein,in the cartridge unit, the housing portion is detachably mounted to thesupplying portion.

{64}

The manufacturing device as set forth in any one of clauses {61} to{63}, wherein the mounting unit is constituted by an at-least uniaxialmovement mechanism.

{65}

The manufacturing device as set forth in any one of clauses {61} to{64}, wherein the collecting unit comprises an at-least uniaxialmovement mechanism.

{66}

The manufacturing device as set forth in any one of clauses {61} to{65}, wherein the cartridge unit is mounted to the mounting unit in anelectrically insulated state.

{67}

The manufacturing device as set forth in any one of clauses {61} to{66}, wherein the mounting unit, the collecting unit, and the powersupply are supported by a common support.

{68}

The manufacturing device as set forth in any one of clauses {61} to{67}, wherein, in the cartridge unit, the housing portion, the supplyingportion, and the nozzle are directly connected.

{69}

An ultrathin sheet manufacturing method for manufacturing an ultrathinsheet having a thickness from 5.1 to 500 μm by ejecting a materialliquid from a nozzle and depositing, onto a collecting unit, fibers orparticles produced from the material liquid, the method comprising

-   -   an intended-shape forming step of ejecting, based on information        relating to an intended contour shape of the ultrathin sheet,        the material liquid within a range of the contour shape of the        ultrathin sheet while moving at least either the nozzle or the        collecting unit, wherein,    -   in the intended-shape forming step, the material liquid is        ejected so as to form a tapered peripheral edge region having a        width of 5 mm or less and having a thickness that gradually        increases inward from a peripheral edge of the contour shape.

EXAMPLES

The present invention will be described in further detail belowaccording to examples. The scope of the present invention, however, isnot limited to the following examples. Unless specifically statedotherwise, refers to “mass % (percent by mass)”.

Examples 1 to 9

A nanofiber layer having a planar-view shape, in which a plurality ofcurvilinear sections with different curvatures form projections anddepressions as illustrated in FIG. 1, was manufactured such that thewidth of the gradation region was 3 mm or greater, or 4 mm or greater.The nanofiber layer had a maximum length of 30 mm in its planar-viewshape. More specifically, a nanofiber layer constituted by nanofibersmade from polyvinyl butyral (PVB; S-LEC B BM-1 from Sekisui ChemicalCo., Ltd.) was formed according to the aforementioned manufacturingmethod. The thickness of the nanofibers was 100 nm. The nanofiber layerwas formed by an electrospinning method, using a material liquidcontaining 12% of PVB, 61.25% of ethanol, 26.25% of 1-butanol, and 0.5%of a quaternary salt-type surfactant (product name “Sanisol C” from KaoCorporation). The conditions for executing the electrospinning methodwere as follows: voltage: 30 kV; separation distance between the nozzletip and the counter electrode: 200 mm; ejection amount: 1 ml/h.Deposition of fibers by electrospinning was performed by moving thenozzle in the planar direction. For the obtained nanofiber layer, thethickness D1 of the peripheral edge of the nanofiber layer, the width W1of the gradation region, and the thickness D3 of the maximum thicknessportion 15 were measured according to the aforementioned measurementmethods. The inclination angle θ was calculated from the difference D2in thickness between the peripheral edge 17 of the gradation region Gand the maximum thickness portion 15, and the width W1 of the gradationregion G. The measurement results and calculation results are shown inTable 1 below. According to visual observation, in each of the nanofiberlayers in Examples 1 to 5, the width W1 of the gradation region was thesame over the entire region of the nanofiber layer. According to visualobservation, also in each of the nanofiber layers in Examples 6 to 9,the width W1 of the gradation region was the same over the entire regionof the nanofiber layer. In all of the Examples, each nanofiber layer hada shape wherein the percentage (%), with respect to the entire length ofthe planar-view contour outline, occupied by sections constituted bycurves was 100%. Stated differently, each nanofiber layer had a shapewherein the entire length of the contour outline in a planar view wasconstituted by curves.

Comparative Examples 1 and 2

A nanofiber layer was formed by an electrospinning method according tosimilar conditions as Example 1, except that: a material liquidcontaining 12% of PVB and 88.0% of ethanol was used; the thickness ofthe peripheral edge of the nanofiber layer was set to either 12 μm or 15μm; and the thickness D3 of the maximum thickness portion of thegradation region G was set to either 15 μm or 20 μm. The thickness ofthe nanofibers was 500 nm. The measurement results are shown in Table 1below.

Evaluation:

For each of the nanofiber layers obtained according to the Examples andComparative Examples, the visual recognizability of the nanofiber layerin a state attached to the skin and the appearance of the nanofiberlayer applied with a foundation were evaluated according to thefollowing methods. The evaluation results are shown in Table 1 below.

Visual Recognizability of Nanofiber Layer:

The inner side of the upper arm of a subject was moistened by applying 5mL/cm² of a cosmetic serum (product name “Rise Lotion II (non-greasy)”from Kao Corporation). The first surface—i.e., the protruding surface—ofthe nanofiber layer was attached to that section. Then, the attachednanofiber layer was visually observed, to evaluate the visualrecognizability according to the following criteria. The evaluationresults are shown in Table 1.

A: The entire nanofiber layer is highly transparent, and quality isexcellent in terms that the nanofiber layer is hard to visuallyrecognize.

B: The nanofiber layer's peripheral edge is transparent, and quality isgood in terms that the nanofiber layer is hard to visually recognize.

C: The nanofiber layer has poor transparency, which makes the nanofiberlayer easy to visually recognize, and quality is poor in terms of makingthe nanofiber layer hard to visually recognize.

Appearance of Nanofiber Layer Applied with Foundation:

0.71 mg/cm² of a powder foundation (product name “Sofina PrimavistaPowder Foundation (moist touch) Beige Ochre OS” from Kao Corporation)was applied onto the nanofiber layer attached to the skin in theaforementioned “Visual Recognizability of Nanofiber Layer.” Then, thenanofiber layer was visually observed, to evaluate the appearanceaccording to the following criteria. The evaluation results are shown inTable 1.

A: The nanofiber layer fitted seamlessly in the surrounding skin, andhad a natural finish.

B: The peripheral edge of the nanofiber layer stood out and did not fitin the surrounding skin, and had an unnatural finish.

TABLE 1 Percentage of Thickness D3 of curves occupying Thickness D1 ofmaximum thickness entire length of Visual Appearance of peripheral edgeof Width W1 or portion of Inclination planar-view recognizabilitynanofiber layer nanofiber layer gradation region gradation region angleθ of contour outline of nanofiber applied with (μm) (mm) (μm) gradationregion (%) layer foundation Example 1 0.1 3 mm or greater 3 0.002 100 AA 2 8 3 mm or greater 15 0.134 100 A A 3 9 3 mm or greater 15 0.115 100A A 4 10 3 mm or greater 15 0.095 100 A A 5 0.1 3 mm or greater 5009.460 100 B A 6 0.4 4 mm or greater 15 0.209 100 A A 7 0.6 4 mm orgreater 15 0.206 100 A A 8 1 4 mm or greater 5.5 0.064 100 A A 9 0.1 4mm or greater 15 0.213 100 A A Comparative 1 12 3 mm or greater 15 0.057100 C B Example 2 15 3 mm or greater 20 0.095 100 C B

Table 1 shows that the nanofiber layers according to the Examples arehard to visually recognize in a state attached to the skin, and offer anatural finish by seamlessly fitting in the skin, even when a foundationis applied thereto. In contrast, the nanofiber layers according to theComparative Examples stand out when attached to the skin and arevisually recognizable. Further, the nanofiber layers according to theComparative Examples exhibit a color (shade) that is different from thesurrounding skin when a foundation is applied thereto, and thus do notfit in the skin and result in an unnatural finish.

Evaluation was made according to the following method, regarding thenanofiber layer's concealability of spots and wrinkles on the skin in astate where the nanofiber layer was attached to the skin, and thenanofiber layer's concealability of spots and wrinkles on the skin whena foundation was applied onto the nanofiber layer.

Concealability of Spots and Wrinkles:

As in the method of the aforementioned “Appearance of Nanofiber LayerApplied with Foundation,” each nanofiber layer was attached to a sectionon the skin having spots and wrinkles, and a foundation was appliedthereon. Then, the spots and wrinkles in that section were visuallyobserved, to evaluate concealability according to the followingcriteria.

3: Spots and wrinkles on the skin are concealed to an extent that theyare invisible.

2: Spots and wrinkles on the skin are slightly visible, but are hard tovisually recognize.

1: Spots and wrinkles on the skin are easy to visually recognize.

The evaluation regarding the aforementioned “Concealability of Spots andWrinkles” was performed using the nanofiber layer of Example 4 and ananofiber layer of Example 10. The nanofiber layer of Example 10 wasmanufactured according to the same method as in Example 4, except thatthe thickness D3 of the maximum thickness portion of the gradationregion was set to 50 μm. The evaluation results are shown in Table 2below.

TABLE 2 Concealability of spots and wrinkles Example 4 2 10 3

Nanofiber layers according to the present invention are improved inconcealability by applying a foundation thereon. For example. Examples 4and 10 were able to effectively conceal spots and wrinkles. Further, byincreasing the thickness of the maximum thickness portion of thegradation region, it was possible to conceal spots and wrinkles to anextent that they were invisible.

Reference Example

According to the same procedure as in Example 1, a nanofiber layer wasmanufactured, wherein the thickness at the apex position was 41 μm. Thenanofiber layer had the same planar-view contour as illustrated inFIG. 1. Three-dimensional shape data of the manufactured nanofiber layerwas acquired according to the aforementioned method, and based thereon,a graph illustrating the sectional contour curve was created. FIG. 22illustrates the sectional contour curve from the obtained graph, foundalong a cross section corresponding to the position of line II-II inFIG. 1. Along with the sectional contour curve, FIG. 22 also shows theperipheral edge CP of the nanofiber layer, the gradation region G, andthe apex position CT. In the sectional contour curve illustrated in FIG.22, the thickness D1 of the peripheral edge is 4.5 μm, and the thicknessof the gradation region increases from the peripheral edge CP to theapex position in the shape of a sigmoid curve.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to provide ananofiber sheet including a nanofiber layer that is hard to visuallyrecognize in a state attached to the skin, and a method for using thenanofiber sheet. Further, according to the present invention, it ispossible to manufacture a nanofiber sheet including a nanofiber layerthat is hard to visually recognize in a state attached to the skin.

1-28. (canceled) 29: A nanofiber sheet comprising: a substrate layer;and a nanofiber layer located on one surface side of the substrate layerand containing nanofibers of a polymer compound, wherein: a peripheraledge of the nanofiber layer has a thickness of from 0.1 to 10 μm; andthe nanofiber layer includes at least 3 mm of a gradation region havinga thickness that gradually increases inward from the peripheral edge.30: The nanofiber sheet according to claim 29, wherein the substratelayer includes a region that extends outward from the peripheral edge ofthe nanofiber layer. 31: The nanofiber sheet according to claim 29,wherein the nanofiber layer and the substrate layer are layered in apeelable manner. 32: The nanofiber sheet according to claim 29, whereinthe substrate layer's surface facing the nanofiber layer is flat. 33:The nanofiber sheet according to claim 29, wherein a difference inthickness between an inner end of the gradation region and theperipheral edge is 5 μm or greater. 34: The nanofiber sheet according toclaim 29, wherein a planar-view shape of the nanofiber layer is a shapeincluding, in its contour, a plurality of curvilinear sections havingdifferent curvatures, a shape including, in its contour, a plurality ofrectilinear sections, or a shape including, in its contour, both thecurvilinear sections and the rectilinear sections. 35: The nanofibersheet according to claim 29, wherein: the nanofiber layer is locatedadjacent to the substrate layer; and the substrate layer has airpermeability. 36: The nanofiber sheet according to claim 29, wherein:the nanofiber layer is located adjacent to the substrate layer; and thesubstrate layer has, on a surface facing the nanofiber layer, aplurality of depressions or projections each having a width greater thana fiber diameter of the nanofiber. 37: The nanofiber sheet according toclaim 29, wherein the nanofiber layer is water-insoluble. 38: Thenanofiber sheet according to claim 29, wherein: the nanofiber sheetcomprises an adhesive layer adherable to a surface of an object; and theadhesive layer is located between the substrate layer and the nanofiberlayer, or on a surface of the nanofiber layer on an opposite side fromthe substrate layer. 39: A method for attaching a nanofiber sheet,wherein the nanofiber sheet comprises: a substrate layer; and ananofiber layer located on one surface side of the substrate layer andcontaining nanofibers of a polymer compound, a peripheral edge of thenanofiber layer has a thickness of from 0.1 to 10 μm; and the nanofiberlayer includes at least 3 mm of a gradation region having a thicknessthat gradually increases inward from the peripheral edge, wherein themethod comprises attaching the nanofiber sheet by placing the nanofiberlayer in contact with a surface of an object. 40: The method forattaching the nanofiber sheet according to claim 39, comprisingattaching the nanofiber layer in a moistened state. 41: The method forattaching the nanofiber sheet according to claim 39, comprising beingattached after peeling the substrate layer. 42: The method for attachingthe nanofiber sheet according to claim 39, comprising peeling thesubstrate layer and attaching the nanofiber layer to the surface of askin. 43: A method for manufacturing a nanofiber sheet, comprisingejecting a material liquid from a nozzle while applying a high voltagebetween the nozzle and a counter electrode, and depositing, onto acollecting unit, nanofibers produced from the material liquid byelectrospinning, wherein a predetermined nanofiber sheet including agradation region having a thickness that gradually increases inward froma peripheral edge is manufactured by depositing the nanofibers onto thecollecting unit by moving at least either the nozzle or the collectingunit. 44: The method for manufacturing a nanofiber sheet according toclaim 43, comprising: a path calculation step of determining a movementpath for at least either the nozzle or the collecting unit along whichthe predetermined nanofiber sheet can be formed, the determining beingbased on a correlation between a factor relating to depositiondistribution of the nanofibers and a deposition thickness of thenanofibers; and a deposition step of depositing the nanofibers, whilemoving at least either the nozzle or the collecting unit, in accordancewith the movement path determined in the path calculation step. 45: Themethod for manufacturing a nanofiber sheet according to claim 44,wherein the factor relating to deposition distribution of the nanofibersis one factor, or a combination of two or more factors, selected fromthe group consisting of a movement speed of the nozzle or the collectingunit, an ejection speed of the material liquid, a potential differencebetween the nozzle and the counter electrode, a distance between thenozzle and the collecting unit, an inner diameter of the nozzle, and amaterial of the nozzle. 46: The method for manufacturing a nanofibersheet according to claim 44, wherein: in a planar view, thepredetermined nanofiber sheet includes an inner region surrounded by thegradation region; and in the path calculation step, the movement path iscalculated such that a minimum thickness of the inner region is equal toor greater than a predetermined setting value. 47: The method formanufacturing a nanofiber sheet according to any claim 44, wherein themovement path along which either one of the nozzle or the collectingunit moves is a combination of a path group that includes, in a nestedmanner, a plurality of paths substantially similar to one another, and acrossover line that connects the plurality of paths, or a linear shapethat can be rendered in one stroke. 48: A device for manufacturing ananofiber sheet, comprising: a nozzle configured to eject a materialliquid; a counter electrode located in opposition to the nozzle andconfigured to create an electric field between the nozzle and thecounter electrode; a collecting unit configured to collect nanofibersproduced by electrically stretching the material liquid; and a mechanismconfigured to move at least either the nozzle or the collecting unit,wherein: the manufacturing device is configured to be capable ofdepositing the nanofibers onto the collecting unit while moving at leasteither the nozzle or the collecting unit based on data of a movementpath inputted to a control unit; and data on the movement pathdetermined in the path calculation step of the method for manufacturinga nanofiber sheet according to claim 44 is inputted or is imputable tothe control unit.